Basil II Porphyrogenitus, known as the Bulgar Slayer, was the senior Byzantine emperor from 976 to 1025 CE. Born in 958 CE, he was the eldest son of Romanos II and Theophano. Basil and his brother Constantine VIII were crowned co-emperors in 960 CE, but they were too young to rule effectively after their father's death in 963 CE. The empire was governed by generals Nikephoros Phokas and John Tzimiskes until Basil assumed full control in 976 CE, following John’s death.The early years of Basil's reign were marked by civil wars against powerful generals Bardas Skleros and Bardas Phokas, which he ultimately quelled by 989 CE. Following the stabilization of the empire, Basil focused on military campaigns that expanded Byzantine territory, notably against the First Bulgarian Empire, which had been a significant adversary. He also engaged in campaigns against the Fatimid Caliphate and the Khazar Khaganate, achieving notable victories and securing parts of Crimea and Georgia.Basil II was recognized for his administrative skills, reducing the power of the aristocracy and increasing the imperial treasury. His reign saw the Byzantine Empire reach its greatest territorial extent in four centuries. A significant diplomatic move was his sister Anna's marriage to Vladimir I of Kiev, which facilitated the Christianization of Kievan Rus' and the formation of the Varangian Guard, an elite military unit.Basil's military campaigns against Bulgaria were particularly notable. After initial setbacks, he launched a series of persistent campaigns beginning in 1000 CE, culminating in the decisive Battle of Kleidion in 1014 CE, where he defeated Samuel of Bulgaria and inflicted severe punishment on the captured soldiers. Bulgaria ultimately submitted in 1018 CE, restoring Byzantine control over the region.Basil also campaigned against the Khazars and the Kingdom of Georgia, securing territories and establishing Byzantine influence in the region. His fiscal policies favored small landowners and aimed to limit the power of the wealthy elite, contributing to a period of relative prosperity for the empire's agrarian class.Throughout his reign, Basil II was known for his military prowess and personal involvement in campaigns, earning the loyalty of his army. He maintained a strong military presence and relied on alliances, particularly with the Rus', to bolster his forces. Basil II died on 15 December 1025 CE, having ruled for nearly 50 years, the longest of any Byzantine emperor. His burial was initially planned for the Church of the Holy Apostles, but he requested to be interred at the Church of St. John the Theologian. His reign is often viewed as a high point in Byzantine history, characterized by military success and territorial expansion.