ANDRONICUS I Comnenus, Emperor of Byzantium. — He belonged to a cadet branch of the Comnenian dynasty, being the son of Isaac, the second son of Alexius I. Like his father, he was hostile to the ruling branch, and after being held in prison for a long time by Manuel I Comnenus, he went into exile in the East among Turkish princes, returning to his homeland shortly before Manuel’s death (1180). During the regency for the young Alexius II (1180–82), taking advantage of the conflicts that arose between the Byzantine population, which was inclined toward xenophobia, and the Latin element influential at the imperial court, A. seized control of the government, having himself proclaimed co-emperor with Alexius II, from whom he soon freed himself in order to remain sole master of the empire (1182). At that point, after allowing xenophobia to rage against the Latins, he sought to strengthen his power by pursuing to the death the aristocracy tied to the memory of Manuel I, but this only provoked increasingly serious unrest and rebellions. When, in 1185, Thessalonica was attacked by a Norman-Sicilian expedition, his position became untenable. He fell victim to popular fury after Isaac II was proclaimed emperor (12 Sept. 1185).
A. is depicted as a cultured, shrewd, and astute politician, but lacking in moral sense; instead of saving the Byzantine empire, he aggravated its ills and hastened its ruin.