The Photian Schism was a four-year (863–867) schism between the episcopal sees of Rome and Constantinople. The issue centred on the right of the Byzantine Emperor to depose and appoint a patriarch without approval from the papacy. In 857, Ignatius was deposed or compelled to resign as Patriarch of Constantinople under the Byzantine Emperor Michael III for political reasons. He was replaced the following year by Photius. The pope, Nicholas I, despite previous disagreements with Ignatius, objected to what he considered the improper deposition of Ignatius and the elevation of Photius, a layman, in his place. After his legates exceeded their instructions in 861 by certifying Photius's elevation, Nicholas reversed their decision in 863 by condemning Photius. The situation remained the same until 867. The West had been sending missionaries to Bulgaria. In 867, Photius called a council and excommunicated Nicholas and the entire western Church. That same year, high ranking courtier Basil I usurped the imperial throne from Michael III and reinstated Ignatius as patriarch.

Basil I became an effective and respected monarch, ruling for 19 years, despite being a man with no formal education and little military or administrative experience. Moreover, he had been the boon companion of a debauched monarch and had achieved power through a series of calculated murders. That there was little political reaction to the murder of Michael III is probably due to his unpopularity with the bureaucrats of Constantinople because of his disinterest in the administrative duties of the Imperial office. Also, Michael's public displays of impiety had alienated the Byzantine populace in general. Once in power Basil soon showed that he intended to rule effectively and as early as his coronation he displayed an overt religiosity by formally dedicating his crown to Christ. He maintained a reputation for conventional piety and orthodoxy throughout his reign.

The Frankish emperor Louis II campaigned against the Emirate of Bari continuously from 866 until 871. Louis was allied with the Lombards of southern Italy from the start, but an attempt at joint action with the Byzantine Empire failed in 869. In the final siege of the city of Bari in 871, Louis was assisted by a Slavic fleet from across the Adriatic.

The city fell and the emir was taken captive, bringing the emirate to an end, but a Saracen presence remained at Taranto. Louis himself was betrayed by his Lombard allies six months after his victory and had to leave southern Italy.

Emperor Basil's reign was marked by the troublesome ongoing war with the heretical Paulicians, centered on Tephrike on the upper Euphrates, who rebelled, allied with the Arabs, and raided as far as Nicaea, sacking Ephesus.

The Paulicians were a Christian sect which—persecuted by the Byzantine state—had established a separate principality at Tephrike on Byzantium's eastern border and collaborated with the Muslim emirates of the Thughur, the Abbasid Caliphate's borderlands, against the Empire. At the Battle of Bathys Ryax, the Byzantine led by Basil's general Christopher, won a decisive victory, resulting in the rout of the Paulician army and the death of its leader, Chrysocheir. This event destroyed the power of the Paulician state and removed a major threat to Byzantium, heralding the fall of Tephrike itself and the annexation of the Paulician principality shortly after.

General Nikephoros Phokas (the Elder) succeeded in taking Taranto and much of Calabria in 880. The successes in the Italian peninsula opened a new period of Byzantine domination there. Above all, the Byzantines were beginning to establish a strong presence in the Mediterranean Sea, and especially the Adriatic.

Leo VI, called the Wise was very well read, leading to his epithet. During his reign, the renaissance of letters, begun by his predecessor Basil I, continued; but the Empire also saw several military defeats in the Balkans against Bulgaria and against the Arabs in Sicily and the Aegean. His reign also witnessed the formal discontinuation of several ancient Roman institutions, such as the separate office of Roman consul.

The Basilika was a collection of laws completed c. 892 AD in Constantinople by order of the Byzantine Emperor Leo VI the Wise during the Macedonian dynasty. This was a continuation of the efforts of his father, Basil I, to simplify and adapt the Emperor Justinian I's Corpus Juris Civilis code of law issued between 529 and 534 which had become outdated. The term "Basilika" comes from Greek: Τὰ Βασιλικά meaning "Imperial Laws" and not from the Emperor Basil's name, which though shares the etymology "imperial".

In 894 Stylianos Zaoutzes, leading minister of Leo VI, convinced the emperor to move the Bulgarian market from Constantinople to Thessaloniki. That move affected not only private interests but also the international commercial importance of Bulgaria and the principle of Byzantine–Bulgarian trade, regulated with the Treaty of 716 and later agreements on the most favoured nation basis. The transfer of the Bulgarian market to Thessaloniki cut short the direct access to goods from the east, which under the new circumstances the Bulgarians would have to buy through middlemen, who were close associates of Stylianos Zaoutzes. In Thessaloniki the Bulgarians were also forced to pay higher tariffs to sell their goods, enriching Zaoutzes' cronies.

The ousting of the merchants from Constantinople was a heavy blow for Bulgarian economic interests. The merchants complained to Simeon I, who in turn raised the issue to Leo VI, but the appeal was left unanswered. Simeon, who according to the Byzantine chroniclers was seeking a pretext to declare war and to implement his plans to seize the Byzantine throne, attacked,provoking what has sometimes been called (inappropriately) the first commercial war in Europe.

In 894 a war broke out between Bulgaria and Byzantium after the decision of Emperor Leo VI the Wise, to implement a request of his father-in-law, basileopater Stylianos Zaoutzes, to move the center of the Balkan trade activities from Constantinople to Thessaloniki, turned out inducing higher tariffs on Bulgarian trade. So Bulgaria's Tsar Simeon I defeats the Byzantines near Adrianople, before the year is over. But then the Byzantines turn to their standard method for handling such situations: they bribe a third party to assist, and on this case, they hire the Magyars of the Etelköz State to attack Danube Bulgaria from the northeast. The Magyars cross the Danube in 895, and are victorious over the Bulgars twice. So Simeon withdraws to Durostorum, which he successfully defends, while during 896 he finds some assistance for his side, persuading the usually Byzantine-friendly Pechenegs to help him out. Then, while the Pechenegs began to combat the Magyars on their eastern frontier, Simeon and his father Boris I, the former tsar who left his monastery retreat to assist his heir in the occasion, gather an enormous army and march to the north to defend their empire.

The result was a great Bulgarian victory which forced the Magyars of the Etelköz realm to abandon the steppes of southern Ukraine. The victory allowed Simeon to lead his troops to the south where he decisively defeated the Byzantines in the battle of Boulgarophygon. 

The Battle of Boulgarophygon was fought in the summer of 896 near the town of Bulgarophygon, modern Babaeski in Turkey, between the Byzantine Empire and the First Bulgarian Empire. The result was an annihilation of the Byzantine army which determined the Bulgarian victory in the trade war of 894–896. Despite the initial difficulties in the war against the Magyars, who acted as Byzantine allies, the battle of Boulgarophygon proved to be the first decisive victory of the young and ambitious Bulgarian ruler Simeon I against the Byzantine Empire. Simeon would go on to inflict a number of defeats on the Byzantines in pursuit of his ultimate goal, the throne in Constantinople. The peace treaty that was signed as a result of the battle confirmed the Bulgarian domination in the Balkans.

Leo won a victory against the Emirate of Tarsus, in which the Arab army was destroyed and the Emir himself captured.

The Emirate of Sicily took Taormina, the last Byzantine outpost on the island of Sicily, in 902.

The Sack of Thessalonica in 904 by the Abbasid Caliphate's navy was one of the worst disasters to befall the Byzantine Empire during the reign of Leo VI and even in the 10th century. A Muslim fleet of 54 ships, led by the renegade Leo of Tripoli, who was a recent convert to Islam, set sail from Syria with the imperial capital of Constantinople as its initial target. The Muslims were deterred from attacking Constantinople, and instead turned to Thessalonica, totally surprising the Byzantines, whose navy was unable to react in time. The Abbasid raiders appeared and after a short siege lasting less than four days, the attackers were able to storm the seaward walls, overcome the Thessalonians' resistance, and take the city on 29 July. The sacking continued for a full week before the raiders departed for their bases in the Levant, having freed 4,000 Muslim prisoners while capturing 60 ships, gaining a large amount of loot and 22,000 captives, mostly young people, and destroying 60 Byzantine ships in the process.

Leo VI caused a major scandal with his numerous marriages which failed to produce a legitimate heir to the throne. His first wife Theophano, whom Basil had forced him to marry on account of her family connections to the Martinakioi, and whom Leo hated, died in 897, and Leo married Zoe Zaoutzaina, the daughter of his adviser Stylianos Zaoutzes, though she died as well in 899.

After Zoe's death a third marriage was technically illegal, but he married again, only to have his third wife Eudokia Baïana die in 901. Instead of marrying a fourth time, which would have been an even greater sin than a third marriage (according to the Patriarch Nicholas Mystikos) Leo took as mistress Zoe Karbonopsina. He married her only after she had given birth to a son in 905, but incurred the opposition of the patriarch. Replacing Nicholas Mystikos with Euthymios, Leo got his marriage recognized by the church (albeit with a long penance attached, and with an assurance that Leo would outlaw all future fourth marriages).

The Rus'–Byzantine War of 907 is associated in the Primary Chronicle with the name of Oleg of Novgorod. The chronicle implies that it was the most successful military operation of the Kievan Rus' against the Byzantine Empire. The threat to Constantinople was ultimately relieved by peace negotiations which bore fruit in the Russo-Byzantine Treaty of 907. Pursuant to the treaty, the Byzantines paid a tribute of twelve grivnas for each Rus' boat.

In 906, Admiral Himerios managed to score his first victory over the Arabs. Another victory followed in 909, and in the next year, he led an expedition on the Syrian coast: Laodicea was sacked, its hinterland plundered, and many prisoners captured, with minimal losses.

The Byzantine–Bulgarian war of 913–927 was fought between the Bulgarian Empire and the Byzantine Empire for more than a decade. Although the war was provoked by the Byzantine emperor Alexander's decision to discontinue paying an annual tribute to Bulgaria, the military and ideological initiative was held by Simeon I of Bulgaria, who demanded to be recognized as Tsar and made it clear that he aimed to conquer not only Constantinople but the rest of the Byzantine Empire, as well.

Most of his reign was dominated by co-regents: from 913 until 919 he was under the regency of his mother, while from 920 until 945 he shared the throne with Romanos Lekapenos, whose daughter Helena he married, and his sons. Constantine VII is best known for the Geoponika, an important agronomic treatise compiled during his reign, and his four books, De Administrando Imperio, De Ceremoniis, De Thematibus, and Vita Basilii.

When Leo died in 912, he was succeeded by his younger brother Alexander, who recalled Nicholas Mystikos and expelled Zoe from the palace. Shortly before his death, Alexander provoked a war with Bulgaria. Zoe returned upon Alexander's death in 913, but Nicholas forced her to enter the convent of St. Euphemia in Constantinople after obtaining the promise of the senate and the clergy not to accept her as empress. However, Nicholas' unpopular concessions to the Bulgarians later in the same year weakened his position and in 914 Zoe was able to overthrow Nicholas and replace him as regent. Nicholas was allowed to remain patriarch after reluctantly recognizing her as empress.

Zoe governed with the support of imperial bureaucrats and the influential general Leo Phokas the Elder, who was her favorite. In 919, there was a coup involving various factions, but the opposition to Zoe and Leo Phokas prevailed; in the end the admiral Romanos Lekapenos took power, married his daughter Helena Lekapene to Constantine VII, and forced Zoe back into the convent of Saint Euphemia.

In 915 Zoe's troops defeated an Arab invasion of Armenia, and made peace with the Arabs. 

In 917, Leo Phokas was placed in charge of a large-scale expedition against the Bulgarians. The plan involved a two-pronged assault, one from the south by the main Byzantine army under Leo Phokas, and one from the north by the Pechenegs, who were to be ferried across the Danube by the Byzantine navy under Romanos Lekapenos. In the event, however, the Pechenegs did not help the Byzantines, partly because Lekapenos quarrelled with their leader (or, as Runciman suggests, might have even been bribed by the Bulgarians) and partly because they had already begun plundering on their own, disregarding the Byzantine plan. Left unsupported by both the Pechenegs and the fleet, Phokas suffered a crushing defeat at the hands of Tsar Symeon at the Battle of Acheloos. 

The Battle of Achelous, also known as the Battle of Anchialus, took place on 20 August 917, on the Achelous river near the Bulgarian Black Sea coast, close to the fortress Tuthom (modern Pomorie) between Bulgarian and Byzantine forces. The Bulgarians obtained a decisive victory which not only secured the previous successes of Simeon I, but made him de facto ruler of the whole Balkan Peninsula, excluding the well-protected Byzantine capital Constantinople and the Peloponnese. The battle, which was one of the biggest and bloodiest battles of the European Middle Ages, was one of the worst disasters ever to befall a Byzantine army, and conversely one of the greatest military successes of Bulgaria. Among the most significant consequences was the official recognition of the imperial title of the Bulgarian monarchs, and the consequent affirmation of Bulgarian equality vis-à-vis Byzantium.

The battle of Katasyrtai (Kατασυρται) occurred in the fall of 917, shortly after the striking Bulgarian triumph at Achelous near the village of the same name close to the Byzantine capital Constantinople, (now Istanbul). The result was a Bulgarian victory. The last Byzantine military forces were literally destroyed and the way to Constantinople was opened, but the Serbs rebelled to the west and the Bulgarians decided to secure their rear before the final assault of the Byzantine capital which gave the enemy precious time to recover.

On 25 March 919, at the head of his fleet, Lekapenos seized the Boukoleon Palace and the reins of government. Initially, he was named magistros and megas hetaireiarches, but he moved swiftly to consolidate his position: in April 919 his daughter Helena was married to Constantine VII, and Lekapenos assumed the new title basileopator; on 24 September, he was named Caesar; and on 17 December 919, Romanos Lekapenos was crowned senior emperor.

In subsequent years Romanos crowned his own sons co-emperors, Christopher in 921, Stephen and Constantine in 924, although, for the time being, Constantine VII was regarded as first in rank after Romanos himself. It is notable that, as he left Constantine VII untouched, he was called 'the gentle usurper'. Romanos strengthened his position by marrying his daughters to members of the powerful aristocratic families of Argyros and Mouseles, by recalling the deposed patriarch Nicholas Mystikos, and by putting an end to the conflict with the Papacy over the four marriages of Emperor Leo VI.

Between 920 and 922, Bulgaria increased its pressure on Byzantium, campaigning in the west through Thessaly, reaching the Isthmus of Corinth, and in the east in Thrace, reaching and crossing the Dardanelles to lay siege on the town of Lampsacus. Simeon's forces appeared before Constantinople in 921, when they demanded the deposition of Romanos and captured Adrianople; in 922 they were victorious at Pigae, burning much of the Golden Horn and seizing Bizye.

The Battle of Pegae was fought in the outskirts of Constantinople between the forces of the Bulgarian Empire and the Byzantine Empire during the Byzantine–Bulgarian war of 913–927. The battle took place in a locality called Pegae (i.e. "the spring"), named after the nearby Church of St. Mary of the Spring. The Byzantine lines collapsed at the very first Bulgarian attack and their commanders fled the battlefield. In the subsequent rout most Byzantine soldiers were killed by the sword, drowned or were captured.

In 922 the Bulgarians continued their successful campaigns in Byzantine Thrace, capturing a number of towns and fortresses, including Adrianople, Thrace's most important city, and Bizye. In June 922 they engaged and defeated yet another Byzantine army at Constantinople, confirming the Bulgarian domination of the Balkans. However, Constantinople itself remained outside their reach, because Bulgaria lacked the naval power to launch a successful siege. The attempts of the Bulgarian emperor Simeon I to negotiate a joint Bulgarian–Arab assault on the city with the Fatimids were uncovered by the Byzantine and countered.

In 923, Kourkouas was appointed commander-in-chief of the Byzantine armies along the eastern frontier, facing the Abbasid Caliphate and the semi-autonomous Muslim border emirates. He kept this post for more than twenty years, overseeing decisive Byzantine military successes that altered the strategic balance in the region.

During the 9th century, Byzantium had gradually recovered its strength and internal stability while the Caliphate had become increasingly impotent and fractured. Under Kourkouas's leadership, the Byzantine armies advanced deep into Muslim territory for the first time in almost 200 years, expanding the imperial border. The emirates of Melitene and Qaliqala were conquered, extending Byzantine control to the upper Euphrates and over western Armenia. The remaining Iberian and Armenian princes became Byzantine vassals. Kourkouas also played a role in the defeat of a major Rus' raid in 941 and recovered the Mandylion of Edessa, an important and holy relic believed to depict the face of Jesus Christ.

Desperate to conquer Constantinople, Simeon planned a large campaign in 924 and sent envoys to the Shia Fatimid ruler Ubayd Allah al-Mahdi Billah, who possessed a powerful navy, which Simeon needed. The Ubayd Allah agreed and sent his own representatives back with the Bulgarians to arrange the alliance. However, the envoys were captured by the Byzantines at Calabria. Romanos offered peace to Egypt under the Fatimids, supplementing this offer with generous gifts, and ruined the Fatimids newly formed alliance with Bulgaria.

In the summer of the same year, Simeon arrived at Constantinople and demanded to see the patriarch and the emperor. He conversed with Romanos on the Golden Horn on 9 September 924 and arranged a truce, according to which Byzantium would pay Bulgaria an annual tax, but would be ceded back some cities on the Black Sea coast. 

On 27 May 927, Simeon died of heart failure in his palace in Preslav. Byzantine chroniclers tie his death to a legend, according to which Romanos decapitated a statue which was Simeon's inanimate double, and he died at that very hour. Tsar Simeon I has remained among the most highly valued Bulgarian historical figures.

Peter, Simeon's son, negotiated a peace treaty with the Byzantine government. The Byzantine Emperor Romanos I Lakapenos eagerly accepted the proposal for peace and arranged for a diplomatic marriage between his granddaughter Maria and the Bulgarian monarch. In October 927 Peter arrived near Constantinople to meet Romanos and signed the peace treaty, marrying Maria on 8 November in the church of the Zoödochos Pege. To signify the new era in Bulgaro-Byzantine relations, the princess was renamed Eirene ("peace"). The treaty of 927 actually represents the fruit of Simeon's military successes and diplomatic initiatives, ably continued by his son's government. Peace was obtained with the frontiers restored to those defined in treaties of 897 and 904. The Byzantines recognised the Bulgarian monarch's title of emperor (basileus, tsar) and the autocephalus status of the Bulgarian patriarchate, while the payment of an annual tribute to Bulgaria by the Byzantine Empire was renewed. Peter of Bulgaria would rule peacefully for 42 years.

In 933, Kourkouas renewed the attack against Melitene. Mu'nis al-Muzaffar sent forces to assist the beleaguered city, but in the resulting skirmishes, the Byzantines prevailed and took many prisoners and the Arab army returned home without relieving the city. In early 934, at the head of 50,000 men, Kourkouas again crossed the frontier and marched toward Melitene. The other Muslim states offered no help, preoccupied as they were with the turmoil following Caliph al-Qahir's deposition. Kourkouas again took Samosata and besieged Melitene. Many of the city's inhabitants had abandoned it at the news of Kourkouas's approach and hunger eventually compelled the rest to surrender on 19 May 934. Wary of the city's previous rebellions, Kourkouas only allowed those inhabitants to remain who were Christians or agreed to convert to Christianity. Most did so, and he ordered the remainder expelled. Melitene was fully incorporated into the empire, and most of its fertile land was transformed into an imperial estate (kouratoreia).

In early summer 941, as Kourkouas prepared to resume campaigning in the East, his attention was diverted by an unexpected event: the appearance of a Rus' fleet that raided the area around Constantinople itself. The Byzantine army and navy were absent from the capital, and the appearance of the Rus' fleet caused panic among the populace of Constantinople. While the navy and Kourkouas's army were recalled, a hastily assembled squadron of old ships armed with Greek Fire and placed under the protovestiarios Theophanes defeated the Rus' fleet on June 11, forcing it to abandon its course toward the city. The surviving Rus' landed on the shores of Bithynia and ravaged the defenseless countryside. The patrikios Bardas Phokas hastened to the area with whatever troops he could gather, contained the raiders, and awaited the arrival of Kourkouas's army. Finally, Kourkouas and his army appeared and fell upon the Rus', who had dispersed to plunder the countryside, killing many of them. The survivors retreated to their ships and tried to cross to Thrace under the cover of night. During the crossing, the entire Byzantine navy attacked and annihilated the Rus'.

Following this Rus' distraction, in January 942 Kourkouas launched a new campaign in the East, which lasted for three years. The first assault fell on the territory of Aleppo, which was thoroughly plundered: at the fall of the town of Hamus, near Aleppo, even Arab sources record the capture of 10–15,000 prisoners by the Byzantines. Despite a minor counter-raid by Thamal or one of his retainers from Tarsus in the summer, in autumn Kourkouas launched another major invasion. At the head of an exceptionally large army, some 80,000 men according to Arab sources, he crossed from allied Taron into northern Mesopotamia. Mayyafiriqin, Amida, Nisibis, Dara—places where no Byzantine army had trod since the days of Heraclius 300 years earlier—were stormed and ravaged. The real aim of these campaigns, however, was Edessa, the repository of the "Holy Mandylion". This was a cloth believed to have been used by Christ to wipe his face, leaving an imprint of his features, and subsequently given to King Abgar V of Edessa. To the Byzantines, especially after the end of the Iconoclasm period and the restoration of image veneration, it was a relic of profound religious significance. As a result, its capture would provide the Lekapenos regime with an enormous boost in popularity and legitimacy.

Kourkouas assailed Edessa every year from 942 onward and devastated its countryside, as he had done at Melitene. Finally, its emir agreed to a peace, swearing not to raise arms against Byzantium and to hand over the Mandylion in exchange for the return of 200 prisoners. The Mandylion was conveyed to Constantinople, where it arrived on August 15, 944, on the feast of the Dormition of the Theotokos. A triumphal entry was staged for the venerated relic, which was then deposited in the Theotokos of the Pharos church, the palatine chapel of the Great Palace. As for Kourkouas, he concluded his campaign by sacking Bithra (modern Birecik) and Germanikeia (modern Kahramanmaraş).

Prince Igor of Kiev was able to mount a new naval campaign against Constantinople as early as 944/945. Under threat from an even larger force than before, the Byzantines opted for diplomatic action to circumvent invasion. They offered tribute and trade privileges to the Rus'. The Byzantine offer was discussed between Igor and his generals after they reached the banks of the Danube, eventually accepting them. The Rus'–Byzantine Treaty of 945 was ratified as a result. This established friendly relations between the two sides.

Romanos kept and maintained power until 16/20 December 944, when he was deposed by his sons, the co-emperors Stephen and Constantine. Romanos spent the last years of his life in exile on the Island of Prote as a monk and died on 15 June 948. With the help of his wife, Constantine VII succeeded in removing his brothers-in-law, and on 27 January 945, Constantine VII became sole emperor at the age of 39, after a life spent in the shadow. Several months later, on 6 April (Easter), Constantine VII crowned his own son Romanos II co-emperor. Having never exercised executive authority, Constantine remained primarily devoted to his scholarly pursuits and delegated his authority to bureaucrats and generals, as well as to his energetic wife Helena Lekapene.

Constantine continued the agrarian reforms of Romanos I and sought to rebalance wealth and tax responsibilities, thus, the larger estate owners (dynatoi) had to return lands they had acquired from the peasantry since 945 CE without being given any compensation in return. For land acquired between 934 and 945 CE, the peasants were required to repay the fee they had received for their land. The land rights of soldiers were likewise protected by new laws. Because of these reforms “the condition of the landed peasantry - which formed the foundation of the whole economic and military strength of the empire - was better off than it had been for a century” (Norwich, 183).

Constantine VII launched a new fleet of 100 ships (20 dromons, 64 chelandia, and 10 galleys) against the Arab corsairs hiding in Crete, but this attempt also failed. In the same year, the Byzantines conquered Germanicea, repeatedly defeated the enemy armies, and in 952 they crossed the upper Euphrates. But in 953, the Hamdanid amir Sayf al-Daula retook Germanicea and entered the imperial territory. The land in the east was eventually recovered by Nikephoros Phokas, who conquered Hadath, in northern Syria, in 958, and by the general John Tzimiskes, who one year later captured Samosata, in northern Mesopotamia. An Arab fleet was also destroyed by Greek fire in 957.

The Battle of Marash was fought in 953 near Marash (modern Kahramanmaraş) between the forces of the Byzantine Empire under the Domestic of the Schools Bardas Phokas the Elder, and of the Hamdanid Emir of Aleppo, Sayf al-Dawla, the Byzantines' most intrepid enemy during the mid-10th century. Despite being outnumbered, the Arabs defeated the Byzantines who broke and fled. Bardas Phokas himself barely escaped through the intervention of his attendants, and suffered a serious wound on his face, while his youngest son and governor of Seleucia, Constantine Phokas, was captured and held a prisoner in Aleppo until his death of an illness some time later. This debacle, coupled with defeats in 954 and again in 955, led to Bardas Phokas' dismissal as Domestic of the Schools, and his replacement by his eldest son, Nikephoros Phokas (later emperor in 963–969).

The Battle of Raban was an engagement fought in autumn 958 near the fortress of Raban between the Byzantine army, led by John Tzimiskes (later emperor in 969–976), and the forces of the Hamdanid Emirate of Aleppo under the famed emir Sayf al-Dawla. The battle was a major victory for the Byzantines, and contributed to the demise of Hamdanid military power, which in the early 950s had proven a great challenge to Byzantium.

Romanos II Porphyrogenitus was Byzantine Emperor from 959 to 963. He succeeded his father Constantine VII at the age of twenty-one and died suddenly and mysteriously four years later. His son Basil II the Bulgar slayer would ultimately succeed him in 976.

The Battle of Andrassos or Adrassos was an engagement fought on 8 November 960 in an unidentified mountain pass on the Taurus Mountains, between the Byzantines, led by Leo Phokas the Younger, and the forces of the Hamdanid Emirate of Aleppo under the emir Sayf al-Dawla.

In mid-960, taking advantage of the absence of much of the Byzantine army on campaign against the Emirate of Crete, the Hamdanid prince launched another invasion of Asia Minor, and raided deeply and widely into the region of Cappadocia. On his return, however, his army was ambushed by Leo Phokas at the pass of Andrassos. Sayf al-Dawla himself barely escaped, but his army was annihilated.

Both contemporary Arab and modern historians, such as Marius Canard and J. B. Bikhazi, have commonly considered the defeat at Andrassos as a decisive engagement that destroyed Hamdanid offensive abilities for good, and opened the path for Nikephoros Phokas' subsequent exploits. 

From the ascension of Emperor Romanos II in 959, Nikephoros and his younger brother Leo Phokas were placed in charge of the eastern and western field armies respectively. In 960, 27,000 oarsmen and marines were assembled to man a fleet of 308 ships carrying 50,000 troops. At the recommendation of the influential minister Joseph Bringas, Nikephoros was entrusted to lead this expedition against the Muslim Emirate of Crete. Nikephoros successfully led his fleet to the island and defeated a minor Arab force upon disembarking near Almyros. He soon began a nine-month siege of the fortress town of Chandax, where his forces suffered through the winter due to supply issues. Following a failed assault and many raids into the countryside, Nikephoros entered Chandax on 6 March 961 and soon wrested control of the entire island from the Muslims. Upon returning to Constantinople, he was denied the usual honor of a triumph, being permitted a mere ovation in the Hippodrome.

The reconquest of Crete was a major achievement for the Byzantines, as it restored Byzantine control over the Aegean littoral and diminished the threat of Saracen pirates, for which Crete had provided a base of operations.

Leo Phokas and Marianos Argyros repelled a major Magyar incursions into the Byzantine Balkans.

Following the conquest of Crete, Nikephoros returned to the east and marched a large and well-equipped army into Cilicia. In February 962 he captured Anazarbos, while the major city of Tarsus ceased to recognize the Hamdanid Emir of Aleppo, Sayf al-Dawla. Nikephoros continued to ravage the Cilician countryside, defeating the governor of Tarsus, ibn al-Zayyat, in open battle; al-Zayyat later committed suicide on account of the loss. Thereafter, Nikephoros returned to the regional capital of Caesarea. Upon the beginning of the new campaigning season al-Dawla entered the Byzantine Empire to conduct raids, a strategy which left Aleppo dangerously undefended. Nikephoros soon took the city of Manbij. In December, an army split between Nikephoros and John I Tzimiskes marched towards Aleppo, quickly routing an opposing force led by Naja al-Kasaki. Al-Dawla's force caught up with the Byzantines, but he too was routed, and Nikephoros and Tzimiskes entered Aleppo on 24 or 23 December. The loss of the city would prove to be both a strategic and moral disaster for the Hamdanids. It was probably on these campaigns that Nikephoros earned the sobriquet, "The Pale Death of the Saracens". During the capture of Aleppo, the Byzantine army took possession of 390,000 silver dinars, 2,000 camels, and 1,400 mules.

The Sack of Aleppo in December 962 was carried out by the Byzantine Empire under Nikephoros Phokas. Aleppo was the capital of the Hamdanid emir Sayf al-Dawla, the Byzantines' chief antagonist at the time. Nikephoros was awarded a second triumph for the fall of Aleppo.

Nikephoros II Phokas was Byzantine emperor from 963 to 969. His brilliant military exploits contributed to the resurgence of the Byzantine Empire during the 10th century. His reign, however, included controversy. In the west, he inflamed conflict with the Bulgarians and saw Sicily completely turn over to the Muslims, while he failed to make any serious gains in Italy following the incursions of Otto I. Meanwhile, in the east, he completed the conquest of Cilicia and even retook the islands of Crete and Cyprus, thus opening the path for subsequent Byzantine incursions reaching as far as Upper Mesopotamia and the Levant. His administrative policy was less successful, as in order to finance these wars he increased taxes both on the people and on the church, while maintaining unpopular theological positions and alienating many of his most powerful allies. These included his nephew John Tzimiskes, who would take the throne after killing Nikephoros in his sleep.

The Byzantine reconquest of Cilicia was a series of conflicts and engagements between the forces of the Byzantine Empire under Nikephoros II Phokas and the Hamdanid ruler of Aleppo, Sayf al-Dawla, over control of the region of Cilicia in southeastern Anatolia. Since the Muslim conquests of the 7th century, Cilicia had been a frontier province of the Muslim world and a base for regular raids against the Byzantine provinces in Anatolia. By the middle of the 10th century, the fragmentation of the Abbasid Caliphate and the strengthening of Byzantium under the Macedonian dynasty allowed the Byzantines to gradually take the offensive. Under the soldier-emperor Nikephoros II Phokas (r. 963–969), with the help of the general and future emperor John I Tzimiskes, the Byzantines overcame the resistance of Sayf al-Dawla, who had taken control of the former Abbasid borderlands in northern Syria, and launched a series of aggressive campaigns that in 964–965 recaptured Cilicia. The successful conquest opened the way for the recovery of Cyprus and Antioch over the next few years, and the eclipse of the Hamdanids as an independent power in the region.

The fall of Taormina to the Aghlabids in 902 marked the effective end of the Muslim conquest of Sicily, but the Byzantines retained a few outposts on the island, and Taormina itself threw off Muslim control soon after. In 909, the Fatimids took over the Aghlabid metropolitan province of Ifriqiya, and with it Sicily. The Fatimids turned their attention to Sicily, where they decided to reduce the remaining Byzantine outposts: Taormina, the forts in the Val Demone and Val di Noto, and Rometta. Taormina fell to the governor Ahmad ibn al-Hasan al-Kalbi on Christmas Day 962, after more than nine months of siege, and in the next year his cousin, al-Hasan ibn Ammar al-Kalbi, laid siege to Rometta. The garrison of the latter sent for aid to Emperor Nikephoros II Phokas, who prepared a major expedition, led by the patrikios Niketas Abalantes and his own nephew, Manuel Phokas.

The Battle of the Straits resulted in a major Fatimid victory, and the final collapse of the attempt of Emperor Nikephoros II Phokas to recover Sicily from the Fatimids.

Upon the death of Ashot III in 967, his two sons, Grigor II (Gregory Taronites) and Bagrat III (Pankratios Taronites), ceded Armenia to the Byzantine Empire in exchange for lands and noble titles. In Byzantium, probably along with other branches of their family already established there in previous decades, they formed the Taronites family, which was one of the senior Byzantine noble families during the 11th–12th centuries. Under Byzantine rule, Taron was united with the district of Keltzene into a single province (theme), whose governor (strategos or doux) usually bore the rank of protospatharios. In the middle of the 11th century, it was united with the theme of Vaspurakan under a single governor. Taron also became a metropolitan see with 21 suffragan sees. 

Since February 967, the Prince of Benevento, Lombard Pandolf Ironhead, had accepted Otto as his overlord and received Spoleto and Camerino as fiefdom. This decision caused conflict with the Byzantine Empire, which claimed sovereignty over the principalities of southern Italy. The eastern Empire also objected to Otto's use of the title Emperor, believing only the Byzantine Emperor Nikephoros II Phokas was the true successor of the ancient Roman Empire. 

The Byzantines opened peace talks with Otto, despite his expansive policy in their sphere of influence. Otto desired both an imperial princess as a bride for his son and successor Otto II as well as the legitimacy and prestige of a connection between the Ottonian dynasty in the West and the Macedonian dynasty in the East. In the following years, both empires sought to strengthen their influence in southern Italy with several campaigns. 

Relations with the Bulgarians worsened. It is likely that Nikephorus bribed the Kievan Rus' to raid the Bulgarians in retaliation for them not blocking Magyar raids. This breach in relations triggered a decades-long decline in Byzantine-Bulgarian diplomacy and was a prelude to the wars fought between the Bulgarians and later Byzantine emperors, particularly Basil II. Svjatoslav and the Rus struck Bulgaria in 968 but they had to retreat to save Kiev from a Pecheneg invasion.

In 967, Sayf al-Dawla, the Emir of Alepppo, died of a stroke, depriving Nikephoros of his only serious challenge in Syria. Sayf had not fully recovered from the sack of Aleppo, which became an imperial vassal shortly thereafter.

Following a year of plunder in Syria, the Byzantine Emperor, Nikephoros II Phokas, decided to return to Constantinople for the winter. Before leaving, however, he constructed the Bagras Fort near Antioch and installed Michael Bourtzes as its commander. Nikephoros explicitly forbade Bourtzes from taking Antioch by force in order to maintain the structural integrity of the city. Bourtzes, however, did not want to wait until winter to take the fortress. He also wanted to impress Nikephoros and earn himself glory, and so he entered into negotiations with the defenders seeking terms for surrender. The Byzantines were able to gain a foothold in the outer defenses of the city.

Following the capture of Antioch, Bourtzes was removed from his position by Nikephoros due to his disobedience, and would go on to assist in a plot which would end in Nikephoros' assassination, while Petros would move deeper into Syrian territory, besieging and taking Aleppo itself and establishing the Byzantine Tributary of Aleppo through the Treaty of Safar.

The plot to assassinate Nikephoros began when he dismissed Michael Bourtzes from his position following his disobedience in the siege of Antioch. Bourtzes was disgraced, and he would soon find an ally with whom to plot against Nikephoros. Towards the end of 965, Nikephoros had John Tzimiskes exiled to eastern Asia Minor for suspected disloyalty, but was recalled on the pleading of Nikephoros' wife, Theophano. According to Joannes Zonaras and John Skylitzes, Nikephoros had a loveless relationship with Theophano. He was leading an ascetic life, whereas she was secretly having an affair with Tzimiskes. Theophano and Tzimiskes plotted to overthrow the emperor. On the night of the deed, she left Nikephoros' bedchamber door unlocked, and he was assassinated in his apartment by Tzimiskes and his entourage on 11 December 969. Following his death, the Phokas family broke into insurrection under Nikephoros' nephew Bardas Phokas, but their revolt was promptly subdued as Tzimiskes ascended the throne.

John I Tzimiskes was the senior Byzantine Emperor from 11 December 969 to 10 January 976. An intuitive and successful general, he strengthened the Empire and expanded its borders during his short reign.

The tributary of Aleppo was soon assured under the Treaty of Safar. In a series of campaigns against the Kievan Rus' encroachment on the Lower Danube in 970–971, he drove the enemy out of Thrace in the Battle of Arcadiopolis, crossed Mt. Haemus, and besieged the fortress of Dorostolon (Silistra) on the Danube for sixty-five days, where after several hard-fought battles he defeated Great Prince Svyatoslav I of Rus'. In 972, Tzimiskes turned against the Abbasid Empire and its vassals, beginning with an invasion of Upper Mesopotamia. A second campaign, in 975, was aimed at Syria, where his forces took Homs, Baalbek, Damascus, Tiberias, Nazareth, Caesarea, Sidon, Beirut, Byblos, and Tripoli, but they failed to take Jerusalem.

The Battle of Arcadiopolis was fought in 970 between a Byzantine army under Bardas Skleros and a Rus' army, the latter also including allied Bulgarian, Pecheneg, and Hungarian (Magyar) contingents. In the preceding years, the Rus' ruler Sviatoslav had conquered northern Bulgaria, and was now menacing Byzantium as well. The Rus' force had been advancing through Thrace towards Constantinople when it was met by Skleros' force. Having fewer men than the Rus', Skleros prepared an ambush and attacked the Rus' army with a portion of his force. The Byzantines then feigned retreat, and succeeded in drawing off the Pecheneg contingent into the ambush, routing it. The remainder of the Rus' army then suffered heavy casualties from the pursuing Byzantines. The battle was important as it bought time for the Byzantine emperor John I Tzimiskes to settle his internal problems and assemble a large expedition, which eventually defeated Sviatoslav the next year.

The Battle of Arcadiopolis was fought in 970 between a Byzantine army under Bardas Skleros and a Rus' army, the latter also including allied Bulgarian, Pecheneg, and Hungarian (Magyar) contingents. In the preceding years, the Rus' ruler Sviatoslav had conquered northern Bulgaria, and was now menacing Byzantium as well. The Rus' force had been advancing through Thrace towards Constantinople when it was met by Skleros' force. Having fewer men than the Rus', Skleros prepared an ambush and attacked the Rus' army with a portion of his force. The Byzantines then feigned retreat, and succeeded in drawing off the Pecheneg contingent into the ambush, routing it. The remainder of the Rus' army then suffered heavy casualties from the pursuing Byzantines. The battle was important as it bought time for the Byzantine emperor John I Tzimiskes to settle his internal problems and assemble a large expedition, which eventually defeated Sviatoslav the next year.

The Battle of Alexandretta was the first clash between the forces of the Byzantine Empire and the Fatimid Caliphate in Syria. It was fought in early 971 near Alexandretta, while the main Fatimid army was besieging Antioch, which the Byzantines had captured two years previously. The Byzantines, led by one of Emperor John I Tzimiskes' household eunuchs, lured a 4,000-strong Fatimid detachment to attack their empty encampment and then attacked them from all sides, destroying the Fatimid force. The defeat at Alexandretta, coupled with the Qarmatian invasion of southern Syria, forced the Fatimids to lift the siege and secured Byzantine control of Antioch and northern Syria.

After being occupied with suppressing the revolt of Bardas Phokas throughout the year 970, Tzimiskes marshalled his forces in early 971 for a campaign against the Rus', moving his troops from Asia to Thrace and gathering supplies and siege equipment. The Byzantine navy accompanied the expedition, tasked with carrying troops to effect a landing in the enemy's rear and to cut off their retreat across the Danube. The emperor chose Easter week of 971 to make his move, catching the Rus' completely by surprise: The passes of the Balkan mountains had been left unguarded, either because the Rus' were busy suppressing Bulgarian revolts or perhaps (as A.D. Stokes suggests) because a peace agreement that had been concluded after the battle of Arcadiopolis made them complacent.

The Byzantine army, led by Tzimiskes in person and numbering 30,000–40,000, advanced quickly and reached Preslav unmolested. The Rus' army was defeated in a battle before the city walls, and the Byzantines proceeded to lay siege. The Rus' and Bulgarian garrison under the Rus' noble Sphangelput up a determined resistance, but the city was stormed on 13 April. Among the captives were Boris II and his family, who were brought to Constantinople along with the Bulgarian imperial regalia. The main Rus' force under Sviatoslav withdrew before the imperial army towards Dorostolon on the Danube. As Sviatoslav feared a Bulgarian uprising, he had 300 Bulgarian nobles executed, and imprisoned many others. The imperial army advanced without hindrance; the Bulgarian garrisons of the various forts and strongholds along the way surrendered peacefully.

After the Byzantines defeated the united Rus'-Bulgarian forces in the Battle of Arcadiopolis and recaptured Pereyaslavets, Svyatoslav was forced to flee to the northern fortress of Dorostolon (Drustur/Dorostorum). Emperor John proceeded to lay siege to Dorostolon, which lasted for 65 days. His army was reinforced by a fleet of 300 ships equipped with Greek fire. The Rus' felt they could not break the siege and agreed to sign a peace treaty with the Byzantine Empire, whereby they renounced their interests towards the Bulgarian lands and the city of Chersonesos in Crimea.

Finally recognizing Otto's imperial title, the new eastern emperor John I Tzimisces sent his niece Theophanu to Rome in 972, and she married Otto II on 14 April 972. As part of this rapprochement, the conflict over southern Italy was finally resolved: the Byzantine Empire accepted Otto's dominion over the principalities of Capua, Benevento and Salerno; in return the German Emperor retreated from the Byzantine possessions in Apulia and Calabria.

Melias then advanced against Amid with an army numbering, according to the Arab sources, 50,000 men. The commander of the local garrison, Hezarmerd, called upon Abu Taghlib for aid, and the latter sent his brother, Abu'l-Qasim Hibat Allah, who arrived before the city on 4 July 973. On the next day, a battle was fought before the walls of Amid in which the Byzantines were defeated. Melias and a group of other Byzantine generals were captured on the next day and brought captive to Abu Taghlib.

The Syrian campaigns of John Tzimiskes were a series of campaigns undertaken by the Byzantine emperor John I Tzimiskes against the Fatimid Caliphate in the Levant and against the Abbasid Caliphate in Syria. Following the weakening and collapse of the Hamdanid Dynasty of Aleppo, much of the Near East lay open to Byzantium, and, following the assassination of Nikephoros II Phokas, the new emperor, John I Tzimiskes, was quick to engage the newly successful Fatimid Dynasty over control of the near east and its important cities, namely Antioch, Aleppo, and Caesarea. He also engaged the Hamdanid Emir of Mosul, who was de iure under the suzerainty of the Abbasid Caliph in Baghdad and his Buyid overlords, over control of parts of Upper Mesopotamia (Jazira).

The early years of Basil's reign were dominated by civil wars against two powerful generals from the Anatolian aristocracy; first Bardas Skleros and later Bardas Phokas, which ended shortly after Phokas's death and Skleros's submission in 989. Basil then oversaw the stabilization and expansion of the eastern frontier of the Byzantine Empire and the complete subjugation of the First Bulgarian Empire, its foremost European foe, after a prolonged struggle. Although the Byzantine Empire had made a truce with the Fatimid Caliphate in 987–988, Basil led a campaign against the Caliphate that ended with another truce in 1000. He also conducted a campaign against the Khazar Khaganate that gained the Byzantine Empire part of Crimea and a series of successful campaigns against the Kingdom of Georgia.

Despite near-constant warfare, Basil distinguished himself as an administrator, reducing the power of the great land-owning families who dominated the Empire's administration and military, filling its treasury, and leaving it with its greatest expanse in four centuries. Although his successors were largely incapable rulers, the Empire flourished for decades after Basil's death. One of the most important decisions taken during his reign was to offer the hand of his sister Anna Porphyrogenita to Vladimir I of Kiev in exchange for military support, thus forming the Byzantine military unit known as the Varangian Guard. The marriage of Anna and Vladimir led to the Christianization of the Kievan Rus' and the incorporation of later successor states of Kievan Rus' within the Byzantine cultural and religious tradition. Basil is seen as a Greek national hero but is a despised figure among Bulgarians.

Upon hearing the news of his deposition, Skleros came to an agreement with local Armenian, Georgian and even Muslim rulers who all vowed to support his claims to the imperial crown. He successfully stirred up rebellion among his relatives and adherents in the Asian provinces, rapidly making himself master of Caesaria, Antioch, and most of Asia Minor.

After several navy commanders defected to Skleros's side, he dashed to Constantinople, threatening to blockade the Dardanelles. The rebel navy under Michael Kourtikios raided the Aegean and attempted to blockade the Dardanelles, but were defeated by the Imperial Fleet under the command of Theodoros Karantenos.

Having lost supremacy at sea, Skleros at once laid siege to the town of Nicaea, which was considered a key to the capital. The town was fortified by a certain Manuel Erotikos Komnenos, father of the future emperor Isaac Komnenos and progenitor of the Komnenoi dynasty.

Basil recalled from exile Bardas Phokas the Younger, a general who had revolted in the previous reign and been interned in a monastery for seven years. Phokas proceeded to Sebastea in the East, where his family demesnes were situated. He came to an understanding with David III Kuropalates of Tao, who pledged 12,000 Georgian horsemen under the command of Tornikios to Phokas' aid.

Skleros instantly left Nicaea for the East and defeated Phokas in two battles, but the latter was victorious in a third. The Battles of Pankaleia, Charsianon, Sarvenis were fought in 978 or 979 between the army loyal to the Byzantine emperor Basil II, commanded by Bardas Phokas the Younger, and the forces of the rebel general Bardas Skleros.

On March 24, 979, the two leaders clashed in single combat, with Skleros cutting the right ear of Phocas' horse with his lance before sustaining a grave wound to the head. The rumour of his death put his army to flight, but Skleros himself found shelter with his Muslim allies. Thereupon the rebellion was subdued without difficulty.

Because the Bulgars had been raiding Byzantine lands since 976, the Byzantine government sought to cause dissension among them by allowing the escape of their captive emperor Boris II of Bulgaria. This ploy failed so Basil used a respite from his conflict with the nobility to lead a 30,000-strong army into Bulgaria and besiege Sredets (Sofia) in 986. Taking losses and worried about the loyalty of some of his governors, Basil lifted the siege and returned for Thrace but he fell into an ambush and suffered a serious defeat at the Battle of the Gates of Trajan.

The Battle of the Gates of Trajan was a battle between Byzantine and Bulgarian forces in the year 986. It took place in the pass of the same name, modern Trayanovi Vrata, in Sofia Province, Bulgaria. It was the largest defeat of the Byzantines under Emperor Basil II. After the unsuccessful siege of Sofia he retreated to Thrace, but was surrounded by the Bulgarian army under the command of Samuil in the Sredna Gora mountains. The Byzantine army was annihilated and Basil himself barely escaped.

In a campaign that curiously mimicked Skleros' revolt a decade earlier, Phokas proclaimed himself emperor and overran most of Asia Minor. Skleros was finally recalled to his homeland by Phokas, who took advantage of the Bulgarian wars to aim at the crown. Skleros promptly mustered an army to support Phokas's cause, but his plans of profiting from the attendant disorders were frustrated when Phokas had him committed to prison. Phokas proceeded to lay siege to Abydos, thus threatening to blockade the Dardanelles. The western army had been annihilated at the Battle of Trajan Gates and was still rebuilding. At this point Basil II obtained timely aid, in the form of 6,000 Varangian mercenaries, from his brother-in-law Vladimir, the Rus prince of Kiev, and marched to Abydos.

The two armies were facing each other, when Phokas galloped forward, seeking personal combat with the Emperor who was riding in front of the lines. Just as he prepared to charge at Basil, however, Phokas suffered a seizure, fell from his horse, and was found to be dead. His head was cut off and brought to Basil. This ended the rebellion.

Despite the inherently destructive nature of most rebellions, Bardas Phokas' rebellion, in fact, provided the Byzantine Empire with many long-term benefits. The most glaring of these was that the resources-depleted David III was now in no position to withstand a concentrated Byzantine attack on his Iberian territories, and his countries were quickly overrun in the years after the civil war in retaliation for his support of Phokas. The Rus' emerged from the civil war the newest Christian state in Europe, and one of the largest, largely as a result of the diplomacy sparked by the rebellion.

To defeat these dangerous rebellions in Anatolia, Basil formed an alliance with Prince Vladimir I of Kiev, who in 988 had captured Chersonesos, the Empire's main base in the Crimean Peninsula. Vladimir offered to evacuate Chersonesos and to supply 6,000 of his soldiers as reinforcements to Basil. In exchange, he demanded to be married to Basil's younger sister Anna. At first, Basil hesitated. The Byzantines viewed all of the peoples of Northern Europe—namely Franks and Slavs—as barbarians. Anna objected to marrying a barbarian ruler because such a marriage would have no precedent in Imperial annals.

Vladimir had researched various religions, having sent delegates to various countries. Marriage was not his main reason for choosing Christianity. When Vladimir promised to baptize himself and to convert his people to Christianity, Basil finally agreed. Vladimir and Anna were married in Crimea in 989. The Rus' warriors taken into Basil's army were instrumental in ending the rebellion; they were later organized into the Varangian Guard. This marriage had important long-term implications, marking the beginning of the process by which the Grand Duchy of Moscow many centuries later would proclaim itself "The Third Rome", and claim the political and cultural heritage of the Byzantine Empire.

In 992, Basil concluded a treaty with the Doge of Venice Pietro II Orseolo under terms reducing Venice's custom duties in Constantinople from 30 nomismata to 17 nomismata. In return, the Venetians agreed to transport Byzantine troops to southern Italy in times of war. According to one estimate, a Byzantine landowning farmer might expect a profit of 10.2 nomismata after paying dues for half of his best-quality land. Basil was popular with the country farmers, the class that produced most of his army's supplies and soldiers. To assure this continued, Basil's laws protected small agrarian property owners and lowered their taxes. Despite the almost constant wars, Basil's reign was considered an era of relative prosperity for the class.

The Battle of the Orontes was fought on 15 September 994 between the Byzantines and their Hamdanid allies under Michael Bourtzes against the forces of the Fatimid vizier of Damascus, the Turkish general Manjutakin. The battle was a Fatimid victory. This defeat led to the direct intervention of Byzantine emperor Basil II in a lightning campaign the next year.

Bourtzes' defeat forced Basil to intervene personally in the East; with his army, he rode through Asia Minor to Aleppo in sixteen days, arriving in April 995. Basil's sudden arrival and the exaggeration of his army's strength circulating in the Fatimid camp caused panic in the Fatimid army, especially because Manjutakin, expecting no threat, had ordered his cavalry horses to be dispersed around the city for pasture. Despite having a considerably larger and well-rested army, Manjutakin was at a disadvantage. He burned his camp and retreated to Damascus without battle. The Byzantines besieged Tripoli unsuccessfully and occupied Tartus, which they refortified and garrisoned with Armenian troops.

The siege of Aleppo was a siege of the Hamdanid capital Aleppo by the army of the Fatimid Caliphate under Manjutakin from the spring of 994 to April 995. Manjutakin laid siege to the city over the winter, while the population of Aleppo starved and suffered from disease. In the spring of 995, the emir of Aleppo appealed for help from Byzantine emperor Basil II. The arrival of a Byzantine relief army under the emperor in April 995 compelled the Fatimid forces to give up the siege and retreat south.

The Battle of Spercheios took place in 997 AD, on the shores of the Spercheios river near the city of Lamia in central Greece. It was fought between a Bulgarian army led by Tsar Samuil, which in the previous year had penetrated south into Greece, and a Byzantine army under the command of general Nikephoros Ouranos. The Byzantine victory virtually destroyed the Bulgarian army, and ended its raids in the southern Balkans and Greece.

In 998, the Byzantines under Damian Dalassenos, the successor of Bourtzes, launched an attack on Apamea but the Fatimid general Jaysh ibn al-Samsama defeated them in battle on 19 July 998. The battle was part of a series of military confrontations between the two powers over control of northern Syria and the Hamdanid emirate of Aleppo. The Byzantine regional commander, Damian Dalassenos, had been besieging Apamea, until the arrival of the Fatimid relief army from Damascus, under Jaysh ibn Samsama. In the subsequent battle, the Byzantines were initially victorious, but a lone Kurdish rider managed to kill Dalassenos, throwing the Byzantine army into panic. The fleeing Byzantines were then pursued, with much loss of life, by the Fatimid troops. This defeat forced the Byzantine emperor Basil II to personally campaign in the region the next year, and was followed in 1001 by the conclusion of a ten-year truce between the two states.

In 1000, a ten-year truce was concluded between the two states. For the remainder of the reign of Al-Hakim bi-Amr Allah (r. 996–1021), relations remained peaceful as al-Hakim was more interested in internal affairs. Even the acknowledgement of Fatimid suzerainty by Abu Muhammad Lu'lu' al-Kabir of Aleppo in 1004 and the Fatimid-sponsored installment of Aziz al-Dawla as the city's emir in 1017 did not lead to a resumption of hostilities, especially because al-Kabir continued to pay tribute to the Byzantines and al-Dawla quickly began acting as an independent ruler. Al-Hakim's persecution of Christians in his realm and especially the 1009 destruction of the Church of the Holy Sepulchre at his orders strained relations and, along with Fatimid interference in Aleppo, provided the main focus of Fatimid–Byzantine diplomatic relations until the late 1030s.

After 1000 the tides of the war turned in favor of the Byzantines under the personal leadership of Basil II, who launched annual campaigns of methodical conquest of the Bulgarian cities and strongholds that were sometimes carried out in all twelve months of the year instead of the usual short campaigning of the epoch with the troops returning home to winter. In 1001, they seized Pliska and Preslav in the east

In 1003, Basil II launched a campaign against the First Bulgarian Empire and after eight months of siege conquered the important town of Vidin to the north-west. The Bulgarian counter strike in the opposite direction towards Odrin did not distract him from his aim and after seizing Vidin he marched southwards through the valley of the Morava destroying the Bulgarian castles on his way. Eventually, Basil II reached the vicinity of Skopje and learned that the camp of the Bulgarian army was situated very close on the other side of the Vardar river.

Samuil of Bulgaria relied on the high waters of the river of Vardar and did not take any serious precautions to secure the camp. Strangely the circumstances were the same as at the battle of Spercheios seven years earlier, and the scenario of the fight was similar. The Byzantines managed to find a fjord, crossed the river and attacked the heedless Bulgarians at night. Unable to resist effectively the Bulgarians soon retreated, leaving the camp and Samuil's tent in the hands of the Byzantines. During this battle Samuil managed to escape and headed east.

The Battle of Kreta occurred in 1009 near the village of Kreta to the east of Thessaloníki. Since the fall of the Bulgarian capital Preslav to the Byzantines in 971, there was a constant state of war between the two Empires. From 976, the Bulgarian noble and later Emperor Samuel successfully fought against the Byzantines but, from the beginning of the 11th century, fortune favoured Byzantium, which recovered from previous severe losses. From 1002 Basil II launched annual campaigns against Bulgaria and seized many towns. In 1009 the Byzantines engaged the Bulgarian army to the east of Thessaloníki. Little is known for the battle itself but the result was a Byzantine victory.

By 1000, Basil had fought off his own nobility and defeated the Islamic threat from the east, and so led another invasion of Bulgaria. This time instead of marching into the middle of the country, he annexed it bit by bit. Eventually, after denying Bulgaria of about a third of its land, the Bulgarians risked everything in one battle in 1014.

The Battle of Kleidion took place in the valley between the mountains of Belasitsa and Ograzhden, near the modern Bulgarian village of Klyuch. The decisive encounter occurred on July 29 with an attack in the rear by a force under the Byzantine general Nikephoros Xiphias, who had infiltrated the Bulgarian positions. The Battle of Kleidion was a disaster for the Bulgarians and the Byzantine army captured 15,000 prisoners; 99 out of every 100 was blinded and the 100th was spared one eye to guide the rest back to their homes. The Bulgarians resisted until 1018 when they finally submitted to Basil II's rule.

The battle of Bitola took place near the town of Bitola, in Bulgarian territory, between a Bulgarian army under the command of the voivode Ivats and a Byzantine army led by the strategos George Gonitsiates. It was one of the last open battles between the First Bulgarian Empire and the Byzantine Empire. The Bulgarians were victorious and the Byzantine Emperor Basil II had to retreat from the Bulgarian capital Ohrid, whose outer walls were by that time already breached by the Bulgarians. However, the Bulgarian victory only postponed the fall of Bulgaria to Byzantine rule in 1018.

In 1017 Basil II invaded Bulgaria with a large army including Rus' mercenaries. His objective was the town of Kastoria which controlled the road between Thessaly and the coast of modern Albania. Basil took the small fortress of Setina located between Ostrovo and Bitola to the south of the river Cherna.

The Bulgarians under the command of Ivan Vladislav marched to the Byzantine camp. Basil II sent strong units under Diogenes to repulse the Bulgarians but the troops of the Byzantine commander were ambushed and cornered. To save Diogenes, the 60-year-old Byzantine Emperor moved on with the rest of his army. When the Bulgarians understood that they retreated chased by Diogenes. According to the Byzantine historian John Skylitzes the Bulgarians had many casualties and 200 were taken prisoners.

After the Battle of Kleidon, resistance continued for four more years under Gavril Radomir and Ivan Vladislav but after the demise of the latter during the siege of Dyrrhachium the nobility surrendered to Basil II and Bulgaria was annexed by the Byzantine Empire. The Bulgarian aristocracy kept its privileges, although many noblemen were transferred to Asia Minor, thus depriving the Bulgarians of their natural leaders.

Bagrat's son George I launched a campaign to restore the Kuropalates's succession to Georgia and occupied Tao in 1015–1016. He entered in an alliance with the Fatimid caliph of Egypt, al-Hakim, forcing Basil to refrain from an acute response to George's offensive. As soon as Bulgaria was conquered in 1018 and al-Hakim was dead, Basil led his army against Georgia. Preparations for a larger-scale campaign against the Kingdom of Georgia were set, beginning with the re-fortification of Theodosiopolis.

In late 1021, Basil, at the head of a large Byzantine army reinforced by the Varangian Guard, attacked the Georgians and their Armenian allies, recovering Phasiane and continuing beyond the frontiers of Tao into inner Georgia. King George burned the city of Oltisi to prevent it falling to the enemy and retreated to Kola. A bloody battle was fought near the village Shirimni at Lake Palakazio on 11 September; the emperor won a costly victory, forcing George I to retreat northwards into his kingdom. Basil plundered the country and withdrew for winter to Trebizond.

George received reinforcements from the Kakhetians, and allied himself with the Byzantine commanders Nicephorus Phocas and Nicephorus Xiphias in their abortive insurrection in the emperor's rear. In December, George's ally, the Armenian king Senekerim of Vaspurakan, being harassed by the Seljuk Turks, surrendered his kingdom to the emperor. During the spring of 1022, Basil launched a final offensive, winning a crushing victory over the Georgians at Svindax. Menaced both by land and sea, King George handed over Tao, Phasiane, Kola, Artaan and Javakheti, and left his infant son Bagrat a hostage in Basil's hands. In the aftermath of the conflict, George I of Georgia was forced to negotiate a peace treaty ending the Byzantine-Georgian wars over the succession of the domains of David III of Tao.

Basil II later secured the annexation of the sub-kingdoms of Armenia and a promise that its capital and surrounding regions would be willed to Byzantium following the death of its king Hovhannes-Smbat. In 1021, he also secured the cession of the Kingdom of Vaspurakan by its king Seneqerim-John, in exchange for estates in Sebasteia.Basil created a strongly fortified frontier in those highlands. Other Byzantine forces restored much of Southern Italy, which had been lost during the previous 150 years.

Basil was preparing a military expedition to recover the island of Sicily when he died on 15 December 1025, having had the longest reign among any Byzantine or Roman emperor. At the time of his death, the Empire stretched from southern Italy to the Caucasus and from the Danube to the Levant, which was its greatest territorial extent since the Muslim conquests four centuries earlier.

Constantine VIII Porphyrogenitus was de jure Byzantine Emperor from 962 until his death. He was the younger son of Emperor Romanos II and Empress Theophano. He was nominal co-emperor for 63 years (longer than any other), successively with his father; stepfather, Nikephoros II Phokas; uncle, John I Tzimiskes; and brother, Basil II. Basil’s death on 15 December 1025 left Constantine as sole emperor. Constantine displayed a lifelong lack of interest in politics, statecraft and the military, and during his brief sole reign the government of the Byzantine Empire suffered from mismanagement and neglect. He had no sons and was instead succeeded by Romanos Argyros, husband of his daughter Zoë.

The start of the decline of the Byzantine Empire has been linked to Constantine's accession to the throne. His reign has been described as "an unmitigated disaster", "a break up of the system" and the cause of "a collapse of the military power of the Empire".

Romanos III Argyros was Byzantine Emperor from 1028 until his death. Romanos has been recorded as a well-meaning but ineffective emperor. He disorganised the tax system and undermined the military, personally leading a disastrous military expedition against Aleppo. He fell out with his wife and foiled several attempts on his throne, including two which revolved around his sister-in-law Theodora. He spent large amounts on the construction and repair of churches and monasteries. He died after six years on the throne, allegedly murdered, and was succeeded by his wife's young lover, Michael IV.

Romanos faced several conspiracies, mostly centred on his sister-in-law Theodora. In 1029 she planned to marry the Bulgarian prince Presian and to usurp the throne. The plot was discovered, Presian was blinded and tonsured as a monk but Theodora was not punished. In 1031 she was implicated in another conspiracy, this time with Constantine Diogenes, the Archon of Sirmium,and was forcibly confined in the monastery of Petrion.

In 1030 Romanos III resolved to lead an army in person against the Mirdasids of Aleppo, despite their having accepted the Byzantines as overlords, with disastrous results. The army camped at a waterless site and its scouts were ambushed. An attack by the Byzantine cavalry was defeated. That night Romanos held an imperial council at which the demoralised Byzantines resolved to abandon the campaign and return to Byzantine territory. Romanos also ordered his siege engines to be burned. On 10 August 1030 the army departed its camp and made for Antioch. Discipline broke down in the Byzantine army, with Armenian mercenaries using the withdrawal as an opportunity to pillage the camp's stores. The Emir of Aleppo launched an attack and the imperial army broke and fled. Only the imperial bodyguard, the Hetaireia, held firm, but Romanos was nearly captured. Accounts vary on the battle losses: John Skylitzes wrote that the Byzantines suffered a "terrible rout" and that some troops were killed in a chaotic stampede by their fellow soldiers, Yahya of Antioch wrote that the Byzantines suffered remarkably few casualties. According to Yahya, two high ranking Byzantine officers were among the fatalities, and another officer was captured by the Arabs. After this defeat the army became a "laughing-stock".

After the defeat at Azaz, Maniakes capture and defends Edessa from the Arabs. He also defeats a Saracen fleet in the Adriatic.

A man of humble origin, Michael owed his elevation to his brother John the Orphanotrophus, an influential and capable eunuch, who brought him to court where the old Macedonian empress Zoe fell in love with him and married him on the death of her husband, Romanus III, in April 1034.

Michael IV the Paphlagonian, handsome and energetic, had poor health and entrusted most of the business of government to his brother. He distrusted Zoë and went to lengths to ensure that he did not suffer the same fate as his predecessor. The fortunes of the Empire under Michael's reign were mixed. His most triumphant moment came in 1041 when he led the imperial army against Bulgarian rebels.

John's reforms of the army and financial system revived the strength of the Empire against its foreign enemies but increased taxes, which caused discontent among the nobility and the commons. John's monopoly of the government and the introduction of such taxes as the Aerikon led to several conspiracies against him and Michael. Poor harvests and famine caused by bad weather and by a locust plague in 1035 exacerbated discontent. When Michael tried to exercise a measure of control over Aleppo, the local citizens drove off the imperial governor. There were revolts at Antioch, Nicopolis and in Bulgaria.

Local Muslim emirs attacked Edessa in 1036 and 1038 CE, the 1036 CE siege being ended only through the timely intervention of Byzantine forces from Antioch. The Georgian army attacked the eastern provinces in 1035 and 1038 CE, although in 1039 CE the Georgian general Liparit invited the Byzantines into Georgia to overthrow Bagrat IV and replace him with his half-brother, Demetre, and although the plot ultimately failed, it allowed the Byzantines to intervene in Georgia in the wars between Liparit and Bagrat for the next two decades.

Michael also concluded a ten-year truce with the Fatimids, after which Aleppo ceased to be a major theater of war for the Byzantine Empire. Byzantium and Egypt each agreed not to aid the enemies of the other. 

On the western front, Michael and John ordered the general George Maniakes to drive the Arabs out of Sicily. Maniakes was assisted by the Varangian Guard, which was at that time led by Harald Hardrada, who later became king of Norway. In 1038 Maniakes landed in southern Italy and soon captured Messina. He then defeated the scattered Arab forces and captured towns in the west and south of the island. By 1040 he had stormed and taken Syracuse. He almost succeeded in driving the Arabs from the island, but Maniakes then fell out with his Lombard allies, while his Norman mercenaries, unhappy with their pay, abandoned the Byzantine general and raised a revolt on the Italian mainland, resulting in the temporary loss of Bari. Maniakes was about to strike against them when he was recalled by John the Eunuch on suspicion of conspiracy. After Maniakes's recall, most of the Sicilian conquests were lost and an expedition against the Normans suffered several defeats, although Bari was eventually recaptured.

Between 1038 and 1040, the Normans fought in Sicily along with the Lombards as mercenaries for the Byzantine Empire against the Kalbids. When the Byzantine general George Maniakes publicly humiliated the Salernitan leader, Arduin, the Lombards withdrew from the campaign, along with the Normans and the Varangian Guard contingent. After Maniakes was recalled to Constantinople, the new catapan of Italy, Michael Doukeianos, appointed Arduin the ruler of Melfi. Melfi, however, soon joined other Apulian Lombards in a revolt against Byzantine rule, in which they were supported by William I of Hauteville and the Normans. The Byzantines, however, managed to buy off the nominal leaders of the revolt – first Atenulf, brother of Pandulf III of Benevento, and then Argyrus. In September 1042, the Normans elected their own leader, ignoring Arduin. The revolt, originally Lombard, had become Norman in character and leadership.

The Uprising of Peter Delyan (Bulgarian: Въстанието на Петър Делян, Greek: Επανάσταση του Πέτρου Δελεάνου), which took place in 1040–1041, was a major Bulgarian rebellion against the Byzantine Empire in the Theme of Bulgaria. It was the largest and best-organised attempt to restore the former Bulgarian Empire until the rebellion of Ivan Asen I and Petar IV in 1185.

The Byzantine Emperor Michael IV prepared a major campaign to finally defeat the Bulgarians. He gathered an elite army of 40,000 men with capable generals and moved constantly in a battle formation. There were a lot of mercenaries in the Byzantine army including Harald Hardråde with 500 Varangians. From Thessaloniki the Byzantines penetrated in Bulgaria and defeated the Bulgarians at Ostrovo in the late summer of 1041. It seems that the Varangians had a decisive role in the victory as their chief is hailed in the Norse sagas as the "devastator of Bulgaria". Though blind, Petar Delyan was in command of the army. His fate is unknown; he either perished in the battle or was captured and taken to Constantinople.

Soon the Byzantines eliminated the resistance of Delyan's remaining voivodes, Botko around Sofia and Manuil Ivats in Prilep, thus ending the Bulgarian revolt.

The Battle of Olivento was fought on 17 March 1041 between the Byzantine Empire and the Normans of southern Italy and their Lombard allies near the Olivento river, in Apulia, southern Italy.

The battle of Olivento was the first of the numerous successes scored by the Normans in their conquest of southern Italy. After the battle, they conquered Ascoli, Venosa, Gravina di Puglia. It was followed by other Normans victories over the Byzantines in the battles of Montemaggiore and Montepeloso.

The Battle of Montemaggiore (or Monte Maggiore) was fought on 4 May 1041, on the river Ofanto near Cannae in Byzantine Italy, between Lombard-Norman rebel forces and the Byzantine Empire. The Norman William Iron Arm led the offence, which was part of a greater revolt, against Michael Dokeianos, the Byzantine Catepan of Italy. Suffering heavy losses in the battle, the Byzantines were eventually defeated, and the remaining forces retreated to Bari. Dokeianos was replaced and transferred to Sicily as a result of the battle. The victory provided the Normans with increasing amounts of resources, as well as a renewed surge of knights joining the rebellion.

On 3 September 1041 at the Battle of Montepeloso, the Normans (nominally under Arduin and Atenulf) defeated Byzantine catepan Exaugustus Boioannes and brought him to Benevento. Around that time, Guaimar IV of Salerno began to attract the Normans. The decisive rebel victory forced the Byzantines to retreat to the coastal cities, leaving the Normans and Lombards in control of the whole interior of southern Italy.

On the night of 18 April to 19 April 1042, Michael V banished his adoptive mother and co-ruler Zoe, for plotting to poison him, to the island of Principo, thus becoming sole Emperor. His announcement of the event in the morning led to a popular revolt; the palace was surrounded by a mob demanding Zoe's immediate restoration. The demand was met, and Zoe was brought back, though in a nun's habit. Presenting Zoe to the crowds in the Hippodrome did not quell the public's outrage over Michael's actions. The masses attacked the palace from multiple directions. The Emperor's soldiers attempted to fight them off and by April 21, an estimated three thousand people from both sides had died. Once inside the palace, the mob pillaged valuables and tore up the tax rolls. Also on 21 April 1042 Zoe's sister Theodora, who had been removed from her nunnery against her will earlier in the uprising, was declared Empress. In response, Michael fled to seek safety in the monastery of the Stoudion together with his remaining uncle. Although he had taken monastic vows, Michael was arrested, blinded, castrated and sent to a monastery. He died as a monk on 24 August 1042.

Theodora Porphyrogenita became involved in political matters only late into her life. Her father Constantine VIII was co-ruler of the Byzantine Empire for 63 years then sole emperor from 1025 to 1028. After he died, his older daughter Zoë co-ruled with her husbands, then her adopted son Michael V, keeping Theodora closely watched. After two foiled plots, Theodora was exiled to an island monastery in the Sea of Marmara in 1031. A decade later, the people of Constantinople rose against Michael V and insisted that she return to rule alongside her sister Zoë.  For 16 months she ruled as empress in her own right before succumbing to a sudden illness and dying at 76. She was the last ruler of the Macedonian line.

Constantine IX Monomachos, reigned as Byzantine emperor from June 1042 to January 1055. He had been chosen by Empress Zoë Porphyrogenita as a husband and co-emperor in 1042, although he had been exiled for conspiring against her previous husband, Emperor Michael IV the Paphlagonian. They ruled together until Zoë died in 1050, and then ruled with Theodora Porphyrogenita until 1055.

During Constantine's reign, he led the Byzantine Empire in wars against groups which included the Kievan Rus', the Pechenegs and in the East against the rising Seljuq Turks. Constantine met these incursions with varying success, nonetheless, the empires borders remained largely intact since the conquests of Basil II, and Constantine would ultimately expand them eastwards, annexing the wealthy Armenian kingdom of Ani. As such he may be considered the last effective ruler of Byzantium’s apogee.

In the year before his death, in 1054, the Great Schism between the Eastern Orthodox and Roman Catholic Churches took place, culminating in Pope Leo IX excommunicating the Patriarch Michael Keroularios. Constantine was aware of the political and religious consequences of such a disunion, but his attempts to prevent it had been futile.

In August 1042, the emperor relieved General George Maniakes from his command in Italy, and Maniakes rebelled, declaring himself emperor in September. The accomplishments of Maniakes in Sicily were largely ignored by the Emperor. The individual particularly responsible for antagonizing Maniakes into revolt was one Romanus Sclerus. Sclerus, like Maniakes, was one of the immensely wealthy landowners who owned large areas of Anatolia – his estates neighboured those of Maniakes and the two were rumoured to have attacked each other during a squabble over land. Sclerus owed his influence over the emperor to his famously charming sister Sclerina, who, in most areas was a highly positive influence on Constantine. Finding himself in a position of power, Sclerus used it to poison Constantine against Maniakes – ransacking the latter's house and even seducing his wife, using the charm his family were famed for. Maniakes' response, when faced with Sclerus demanding that he hand command of the empire's forces in Apulia over to him, was to brutally torture the latter to death, after sealing his eyes, ears, nose and mouth with excrement. Maniakes was then proclaimed emperor by his troops (including the Varangians) and marched towards Constantinople. In 1043 his army clashed with troops loyal to Constantine near Thessalonika, and though initially successful, Maniakes was killed during the melee after receiving a fatal wound (according to Psellus' account). Constantine's extravagant punishment of the surviving rebels was to parade them in the Hippodrome, seated backwards on donkeys. With his death, the rebellion ceased.

The final Byzantine–Russian War was, in essence, an unsuccessful naval raid against Constantinople instigated by Yaroslav I of Kiev and led by his eldest son, Vladimir of Novgorod, in 1043.

The reasons for the war are disputed, as is its course. Michael Psellus, an eyewitness of the battle, left a hyperbolic account detailing how the invading Kievan Rus' were annihilated by a superior Imperial fleet with Greek fire off the Anatolian shore. According to the Slavonic chronicles, the Russian fleet was destroyed by a tempest.

In 1047 Constantine was faced by the rebellion of his nephew Leo Tornikios, who gathered supporters in Adrianople and was proclaimed emperor by the army. Tornikios was forced to retreat, failed in another siege, and was captured during his flight.

In 1045 Constantine annexed the Armenian kingdom of Ani, but this expansion merely exposed the empire to new enemies. In 1046 the Byzantines came into contact for the first time with the Seljuk Turks. They met at the Battle of Kapetron in Armenia in 1048 and settled a truce the following year.

The Tornikios Revolt had weakened Byzantine defenses in the Balkans, and in 1048 the area was raided by the Pechenegs, who continued to plunder it for the next five years. The emperor's efforts to contain the enemy through diplomacy merely exacerbated the situation, as rival Pecheneg leaders clashed on Byzantine ground, and Pecheneg settlers were allowed to live in compact settlement in the Balkans, making it difficult to suppress their rebellion.

The Pecheneg revolt lasted from 1049 to 1053. Although the conflict ended with a negotiation of favorable terms with the rebels, it also demonstrated the deterioration of the Byzantine army. Its inability to defeat the rebels foreshadowed the future losses against the Seljuk Turks in the east and the Normans in the west.

About 1053, Constantine IX disbanded what the historian John Skylitzes calls the "Iberian Army", converting its obligations from military service to the payment of tax, and it was turned into a contemporary Drungary of the Watch. Two other knowledgeable contemporaries, the former officials Michael Attaleiates and Kekaumenos, agree with Skylitzes that by demobilising these soldiers Constantine did catastrophic harm to the Empire's eastern defences.

The Battle of Zygos Pass was a battle between the Byzantine Empire and the Pechenegs. To combat the Pecheneg revolt, Byzantine Emperor Constantine IX sent a Byzantine army under the command of Basil the Synkellos, Nikephoros III, and the Doux of Bulgaria, to guard the Danube. Whilst marching to their station, the Pechenegs ambushed and destroyed the Byzantine army. Surviving troops, led by Nikephoros, escaped. They traveled for 12 days to Adrianople, while under constant Pecheneg attacks. Nikephoros III first gained notoriety after his actions during the battle. Resulting in a promotion to magistros. As a consequence of the Byzantine defeat at this battle, Emperor Constantine IX was forced to sue for peace.

The East–West Schism (also known as the Great Schism or Schism of 1054) was the break of communion which occurred in the 11th century between the Western and Eastern churches. Immediately following the schism, it is estimated that Eastern Christianity comprised a slim majority of Christians worldwide, with the majority of remaining Christians being Western. The schism was the culmination of theological and political differences which had developed during the preceding centuries between Eastern and Western Christianity.

• During this period, the Byzantine state reached its greatest extent since the Muslim conquests. The empire also expanded during this period, conquering Crete, Cyprus, and most of Syria.
• The Macedonian Dynasty saw the Byzantine Renaissance, a time of increased interest in classical scholarship and the assimilation of classical motifs into Christian artwork. The ban on painting religious figures and idols was lifted and the era produced classical representations and mosaics depicting them.
• However, the Macedonian Dynasty also saw increasing dissatisfaction and competition for land among nobles in the theme system, which weakened the authority of the emperors and led to instability. Throughout this period there was great competition among nobles for land in the theme system. Since such governors could collect taxes and control the military forces of their themes, they became independent of the emperors and acted independently, weakening the authority of the emperors. They tended to increase taxes on small farmers in order to enrich themselves, thereby causing massive dissatisfaction.
• The Macedonian period also included events of momentous religious significance. The conversion of the Bulgarians, Serbs, and Rus’ to Orthodox Christianity permanently changed the religious map of Europe, and still impacts demographics today. Cyril and Methodius, two Byzantine Greek brothers, contributed significantly to the Christianization of the Slavs, and in the process devised the Glagolitic alphabet, ancestor to the Cyrillic script.

When Constantine died, the 74-year-old Theodora returned to the throne despite fierce opposition from court officials and military claimants. For 16 months she ruled as empress in her own right.

When Theodora was seventy-six, the patriarch Michael Keroularios advocated that Theodora advance a subject to the throne through marriage to her, in order to assure a succession. She refused to consider marriage, no matter how token. She also refused to name an heir to the throne. Theodora became gravely ill with an intestinal disorder in late August 1056. On 31 August her advisors, chaired by Leo Paraspondylos, met to decide whom to recommend to her as a successor. According to Psellus, they selected Michael Bringas, an aged civil servant and former military finance minister whose main attraction was that "he was less qualified to rule than he was to be ruled and directed by others". Theodora was unable to speak, but Paraspondylos decided that she had nodded at an appropriate moment. Hearing of this the Patriarch refused to believe it. Eventually he was persuaded and Bringas was crowned as Michael VI. Theodora died a few hours later and with her death, the Macedonian dynasty's 189-year rule ended.