Aaron (; ; ) was a younger son of the last Tsar of the First Bulgarian Empire, Ivan Vladislav (). After the Byzantine conquest of Bulgaria he entered Byzantine service along with his brothers, and held a series of higher military commands in the eastern provinces of the Byzantine Empire during the 1040s and 1050s, rising from patrikios to protoproedros in the process. In this capacity, he fought in the first battles against the invading Seljuq Turks, as well as, unsuccessfully, against the uprising in 1057 of his brother-in-law Isaac I Komnenos. The Aaronios noble family was named after him, and included his descendants, as well as the descendants of his siblings. Life He was the third son of Ivan Vladislav and Maria. He had two older brothers, Presian and Alusian, as well as three younger ones, and six sisters. After the death of Ivan Vladislav in February 1018, Bulgarian resistance to the decades-long attacks of the Byzantine emperor Basil II () collapsed, and Aaron with his two older brothers fled to Mount Tmoros in Tomornitsa. Basil surrounded the mountain with troops, and the three brothers eventually surrendered, after receiving guarantees for their safety. Presian received the high title of magistros (suggesting that he was the eldest son, and his father's heir)), while Alusian and Aaron received the slightly lower title of patrikios. Presian was later involved in a plot to usurp the throne from Emperor Romanos III Argyros in , resulting in him being blinded and exiled to a monastery, and the second brother, Alusian, was involved in the failed Uprising of Peter Delyan in 1040, usurping its leadership before betraying it to the Byzantines. Military career Aaron himself is known from both literary sources and his seals of office to have served as military governor (katepano) of Vaspurakan in ; at this time, as shown by his seals, he bore the titles of patrikios, anthypatos, and vestes) . During this time Aaron, alongside Katakalon Kekaumenos, the katepano of Ani, faced the first large-scale invasions of the Seljuq Turks into Byzantine-held Armenia. The first invasion, led by Hasan the Deaf, was destroyed by the two Byzantine commanders east of Lake Van in 1048. Hasan's attack was soon followed by an even larger expedition, led by Ibrahim Inal, which the local Byzantine forces were unable to counter. According to the historian John Skylitzes, contrary to Kekaumenos, who wanted to confront