Byzantine Empire: Angelid dynasty

Isaac II Angelos was Byzantine Emperor from 1185 to 1195, and again from 1203 to 1204. His father Andronikos Doukas Angelos was a military leader in Asia Minor (c. 1122 – aft. 1185) who married Euphrosyne Kastamonitissa (c. 1125 – aft. 1195). Andronikos Doukas Angelos was the son of Constantine Angelos and Theodora Komnene (b. 15 January 1096/1097), the youngest daughter of Emperor Alexios I Komnenos and Irene Doukaina. Thus Isaac was a member of the extended imperial clan of the Komnenoi.

Isaac inaugurated his reign with a decisive victory over the Norman King of Sicily, William II, at the Battle of Demetritzes on 7 November 1185. William had invaded the Balkans with 80,000 men and 200 ships towards the end of Andronikos I's reign. William II had recently sacked and captured the Byzantine Empire's second city, Thessalonica. It was a decisive Byzantine victory, which led to the immediate re-occupation of Thessalonica and ended the Norman threat to the Empire.

The remnants of the Norman army fled by sea with many ships being subsequently lost to storms. Any Normans who did not manage to escape from Thessalonica were massacred by the Alan troops of the Byzantine army in revenge for the deaths of their kinsmen when the city was sacked. The Norman fleet under Tancred of Lecce, which was in the Sea of Marmara, also withdrew. The city of Dyrrhachium on the Adriatic coast was the only part of the Balkans that remained in Norman hands and this fell the following Spring after a siege, effectively ending the attempted Sicilian conquest of the Empire. The Kingdom of Sicily had suffered enormous losses in killed and captured. More than four thousand captives were sent to Constantinople, where they suffered great mistreatment at the hands of Isaac II.

In late 1185, Isaac sent a fleet of 80 galleys to liberate his brother Alexius III from Acre, but the fleet was destroyed by the Normans of Sicily. He then sent a fleet of 70 ships, but it failed to recover Cyprus from the rebellious noble Isaac Komnenos, thanks to Norman interference.

The oppressiveness of Isaac II's taxes, increased to pay his armies and finance his marriage, resulted in a Vlach-Bulgarian uprising late in 1185. The Uprising of Asen and Peter was a revolt of Bulgarians and Vlachs living in Moesia and the Balkan Mountains, then the theme of Paristrion of the Byzantine Empire, caused by a tax increase. It began on 26 October 1185, the feast day of St. Demetrius of Thessaloniki, and ended with the restoration of Bulgaria with the creation of the Second Bulgarian Empire, ruled by the Asen dynasty.

Branas held the new emperor Isaac II Angelos in contempt, this, combined with his successes as a general and connections to the former imperial dynasty of the Komnenoi, emboldened him to aspire to the throne.

In 1187, Branas was sent to counter the Vlach-Bulgarian Rebellion and Niketas Choniates praised him for his deeds against the rebels. This time, in contrast to his loyalty to Andronikos I, he did rebel; he was proclaimed emperor in his native city of Adrianople, where he mustered his troops and gained the backing of his kinsmen. Branas then advanced on Constantinople, where his troops gained an initial success against the defending army. However, he was unable to pierce or bypass by the city's defences, or suborn the defenders, and could not gain entry by any means. The imperial forces led by Conrad of Montferrat, the emperor's brother-in-law, made a sortie. The troops of Branas began to give way under pressure from Conrad's heavily equipped infantry. In response Branas personally attacked Conrad, but his lance thrust did little harm. Conrad then unhorsed Branas, his lance striking the cheekpiece of Branas' helmet. Once on the ground, Alexios Branas was beheaded by Conrad's supporting footsoldiers. With their leader dead, the rebel army fled the field. Branas' head was taken to the imperial palace, where it was treated like a football, and was then sent to his wife Anna, who (according to the historian Niketas Choniates) reacted bravely to the shocking sight.

In 1189 the Holy Roman Emperor Frederick I Barbarossa sought and obtained permission to lead his troops on the Third Crusade through the Byzantine Empire. But Isaac was suspicious that Barbarossa wished to conquer Byzantium: the reasons for this suspicious attitude were the diplomatic contact of Frederick with the Bulgarians and the Serbians, foes of the Byzantine Empire during this period, also Barbarossa's previous feud with Manuel.

The rumors of 1160s about a German invasion in the Byzantine Empire were still remembered in the Byzantine court during Isaac’s reign. In retaliation Barbarossa's army occupied the city of Philippopolis and defeated a Byzantine army of 3,000 men that attempted to recapture the city.

The Byzantine troops managed to constantly and successfully harass the Crusaders but a group of Armenians revealed to the Germans the strategic plan of the Byzantines. The Crusaders, who outnumbered the Byzantines, caught them unprepared and defeated them. Thus compelled by force of arms, Isaac II was forced to fulfill his engagements in 1190, when he released imprisoned German emissaries who were held in Constantinople, and exchanged hostages with Barbarossa, as a guarantee that the crusaders would not sack local settlements until they departed the Byzantine territory.

The Third Crusade (1189–1192) was an attempt by three European monarchs of Western Christianity (Philip II of France, Richard I of England and Frederick I, Holy Roman Emperor) to reconquer the Holy Land following the capture of Jerusalem by the Ayyubid sultan Saladin in 1187. For this reason, the Third Crusade is also known as the Kings' Crusade.

It was partially successful, recapturing the important cities of Acre and Jaffa, and reversing most of Saladin's conquests, but it failed to recapture Jerusalem, which was the major aim of the Crusade and its religious focus. Spurred by religious zeal, King Henry II of England and King Philip II of France (known as "Philip Augustus") ended their conflict with each other to lead a new crusade. The death of Henry (6 July 1189), however, meant the English contingent came under the command of his successor, King Richard I of England. The elderly German Emperor Frederick Barbarossa also responded to the call to arms, leading a massive army across the Balkans and Anatolia.

The Battle of Tryavna occurred in 1190, in the mountains around the contemporary town of Tryavna, central Bulgaria. The result was a Bulgarian victory over the Byzantine Empire, which secured the successes achieved since the beginning of the Rebellion of Asen and Peter in 1185.

Richard and Philip's sea route meant that they would not have to rely on their Greek counterparts for supplies or permission to pass through. The odd exception came when Richard crushed the rebellion of Isaac Komnenos and refused to hand the island of Cyprus back to Byzantium, using it instead to tame his rebellious vassal Guy of Lusignan, former King of Jerusalem. The new Kingdom of Cyprus would last from 1192 to 1489 before being annexed by the Republic of Venice.

After the major Bulgarian success in the Battle of Tryavna in 1190 their troops launched frequent attacks on Thrace and Macedonia. The Byzantines could not face the fast Bulgarian cavalry which attacked from different directions on a vast area. Towards 1194 Ivan Asen I had taken the important city of Sofia and the surrounding areas as well as the upper valley of the Struma River from where his armies advanced deep into Macedonia.

To distract his attention the Byzantines decided to strike in eastern direction. They assembled the Eastern army under its commander Alexios Gidos and the Western army under its Domestic Basil Vatatzes to stop the dangerous rise of Bulgarian power. Near Arcadiopolis in Eastern Thrace they met the Bulgarian army. After a fierce battle the Byzantine armies were annihilated. Most of Gidos's troops perished and he had to flee for his life, while the Western army was fully slaughtered and Basil Vatatzes was killed on the battlefield. After the defeat Isaac II Angelos forged an alliance with the Hungarian King Bela III against the common enemy. Byzantium had to attack from the south and Hungary was to invade the north-western Bulgarian lands and take Belgrade, Branichevo and eventually Vidin but the plan failed.

Alexios III Angelos reigned under the name Alexios Komnenos, associating himself with the Komnenos dynasty. A member of the extended imperial family, Alexios came to throne after deposing, blinding and imprisoning his younger brother Isaac II Angelos. The most significant event of his reign was the attack of the Fourth Crusade on Constantinople in 1203, on behalf of Alexios IV Angelos. Alexios III took over the defence of the city, which he mismanaged, and then fled the city at night with one of his three daughters. From Adrianople, and then Mosynopolis, he attempted unsuccessfully to rally his supporters, only to end up a captive of Marquis Boniface of Montferrat. He was ransomed, sent to Asia Minor where he plotted against his son-in-law Theodore Laskaris, but was eventually captured and spent his last days confined to the Monastery of Hyakinthos in Nicaea, where he died.

The battle of Serres took place in 1196 near the town of Serres in contemporary Greece between the armies of the Bulgarian and the Byzantine Empire. The result was Bulgarian victory. Instead of a triumphal return, the way back to the Bulgarian capital ended tragically. Slightly before reaching Tarnovo, Ivan Asen I was murdered by his cousin Ivanko, who had been bribed by the Byzantines. Still, their attempts to stop the Bulgarians failed: Ivanko could not take the throne and had to flee to Byzantium. The Bulgarians advanced further during the reign of Kaloyan

The Crusade of 1197 was a crusade launched by the Hohenstaufen emperor Henry VI in response to the aborted attempt of his father, Emperor Frederick I, during the Third Crusade in 1189–90. While his forces were already on their way to the Holy Land, Henry VI died before his departure in Messina on 28 September 1197. The emerging throne conflict between his brother Philip of Swabia and the Welf rival Otto of Brunswick made many higher-ranking crusaders return to Germany in order to protect their interests in the next imperial election. The nobles remaining on the campaign captured the Levant coast between Tyre and Tripoli before returning to Germany. The Crusade ended after the Christians captured Sidon and Beirut from the Muslims in 1198.

Henry VI decided to take advantage of his father's threat of force against the Byzantine Empire, affected by the rebellions in Serbia and Bulgaria as well as by Seljuk incursions. Emperor Isaac II Angelos had maintained close ties with the Sicilian usurper king Tancred of Lecce, but he was overthrown in April 1195 by his brother Alexios III Angelos. Henry took the occasion to exact tribute and had a threatening letter sent to Alexios III in order to finance the planned Crusade. Alexius immediately submitted to the tributary demands and exacted high taxes from his subjects to pay the Crusaders 5,000 pounds of gold. Henry also forged alliances with King Amalric of Cyprus and Prince Leo of Cilicia.

The Fourth Crusade (1202–1204) was a Latin Christian armed expedition called by Pope Innocent III. The stated intent of the expedition was to recapture the Muslim-controlled city of Jerusalem, by first defeating the powerful Egyptian Ayyubid Sultanate, the strongest Muslim state of the time. However, a sequence of economic and political events culminated in the Crusader army's 1202 siege of Zara and the 1204 sack of Constantinople, the capital of the Greek Christian-controlled Byzantine Empire, rather than Egypt as originally planned. This led to the partitioning of the Byzantine Empire by the Crusaders.

The young Alexios was imprisoned in 1195 when Alexios III overthrew Isaac II in a coup. In 1201, two Pisan merchants were employed to smuggle Alexios out of Constantinople to the Holy Roman Empire, where he took refuge with his brother-in-law Philip of Swabia, King of Germany.

According to the contemporary account of Robert of Clari, it was while Alexios was at Swabia's court that he met with Marquis Boniface of Montferrat, Philip's cousin, who had been chosen to lead the Fourth Crusade, but had temporarily left the Crusade during the siege of Zara in 1202 to visit Philip. Boniface and Alexios allegedly discussed diverting the Crusade to Constantinople so that Alexios could be restored to his father's throne. Montferrat returned to the Crusade while it wintered at Zara and he was shortly followed by Prince Alexios's envoys who offered to the Crusaders 10,000 Byzantine soldiers to help fight in the Crusade, maintain 500 knights in the Holy Land, the service of the Byzantine navy (20 ships) in transporting the Crusader army to Egypt, as well as money to pay off the Crusaders' debt to the Republic of Venice with 200,000 silver marks. Additionally, he promised to bring the Greek Orthodox Church under the authority of the pope.

The siege of Constantinople in 1203 was a Crusader siege of the capital of the Byzantine Empire, in support of the deposed emperor Isaac II Angelos and his son Alexios IV Angelos. It marked the main outcome of the Fourth Crusade.

The citizens of Constantinople rebelled in late January 1204, and in the chaos an otherwise obscure nobleman named Nicholas Kanabos was acclaimed emperor, though he was unwilling to accept the crown. The two co-emperors barricaded themselves in the Palace of Blachernae and entrusted Mourtzouphlos with a mission to seek help from the crusaders, or at least they informed him of their intentions. Instead of contacting the crusaders, Mourtzouphlos, on the night of 28–29 January 1204, used his access to the palace to bribe the "ax-bearers" (the Varangian Guard), and with their backing arrest the emperors. The support of the Varangians seems to have been of major importance in the success of the coup, though Mourtzouphlos also had help from his relations and associates. The young Alexios IV was eventually strangled in prison; while his father Isaac, both enfeebled and blind, died at around the time of the coup, his death variously attributed to fright, sorrow, or mistreatment. Kanabos was initially spared and offered an office under Alexios V, but he refused both this and a further summons from the emperor and took sanctuary in the Hagia Sophia; he was forcibly removed and killed on the steps of the cathedral.

Alexios V Doukas was Byzantine emperor from February to April 1204, just prior to the sack of Constantinople by the participants of the Fourth Crusade. His family name was Doukas, but he was also known by the nickname Mourtzouphlos, referring to either bushy, overhanging eyebrows or a sullen, gloomy character. He achieved power through a palace coup, killing his predecessors in the process. Though he made vigorous attempts to defend Constantinople from the crusader army, his military efforts proved ineffective. His actions won the support of the mass of the populace, but he alienated the elite of the city. Following the fall, sack, and occupation of the city, Alexios V was blinded by another ex-emperor and later executed by the new Latin regime. He was the last Byzantine emperor to rule in Constantinople until the Byzantine recapture of Constantinople in 1261.

The sack of Constantinople occurred in April 1204 and marked the culmination of the Fourth Crusade. Crusader armies captured, looted, and destroyed parts of Constantinople, then the capital of the Byzantine Empire. After the capture of the city, the Latin Empire (known to the Byzantines as the Frankokratia or the Latin Occupation) was established and Baldwin of Flanders was crowned Emperor Baldwin I of Constantinople in the Hagia Sophia.

After the city's sacking, most of the Byzantine Empire's territories were divided up among the Crusaders. Byzantine aristocrats also established a number of small independent splinter states, one of them being the Empire of Nicaea, which would eventually recapture Constantinople in 1261 and proclaim the reinstatement of the Empire. However, the restored Empire never managed to reclaim its former territorial or economic strength, and eventually fell to the rising Ottoman Empire in the 1453 Siege of Constantinople.

The sack of Constantinople is a major turning point in medieval history. The Crusaders' decision to attack the world's largest Christian city was unprecedented and immediately controversial. Reports of Crusader looting and brutality scandalised and horrified the Orthodox world; relations between the Catholic and Orthodox churches were catastrophically wounded for many centuries afterwards, and would not be substantially repaired until modern times.

The Byzantine Empire was left much poorer, smaller, and ultimately less able to defend itself against the Seljuk and Ottoman conquests that followed; the actions of the Crusaders thus directly accelerated the collapse of Christendom in the east, and in the long run helped facilitate the later Ottoman Conquests of Southeastern Europe.

The Nicaean–Latin wars were a series of wars between the Latin Empire and the Empire of Nicaea, starting with the dissolution of the Byzantine Empire by the Fourth Crusade in 1204. The Latin Empire was aided by other Crusader states established on Byzantine territory after the Fourth Crusade, as well as the Republic of Venice, while the Empire of Nicaea was assisted occasionally by the Second Bulgarian Empire, and sought the aid of Venice's rival, the Republic of Genoa. The conflict also involved the Greek state of Epirus, which also claimed the Byzantine inheritance and opposed Nicaean hegemony. The Nicaean reconquest of Constantinople in 1261 CE and the restoration of the Byzantine Empire under the Palaiologos dynasty did not end the conflict, as the Byzantines launched on and off efforts to reconquer southern Greece (the Principality of Achaea and the Duchy of Athens) and the Aegean islands until the 15th century, while the Latin powers, led by the Angevin Kingdom of Naples, tried to restore the Latin Empire and launched attacks on the Byzantine Empire.