Wikipedia
Theophobos
Theophobos or Theophobus, originally Nasir , Nasr , or Nusayr , was an Iranian commander of the Khurramites who converted to Christianity and entered Byzantine service under Emperor Theophilos (r. 829–843). Raised to high rank and married into the imperial family, Theophobos was given command of his fellow Khurramites and served under Theophilos in his wars against the Abbasid Caliphate in 837–838. After the Byzantines' defeat at the Battle of Anzen, he was proclaimed emperor by his own men, but did not pursue this claim. Instead he peacefully submitted to Theophilos in the next year and was apparently pardoned, until he was executed by the dying emperor in 842 to prevent a challenge to the accession of Michael III.