Alexios I Megas Komnenos or Alexius I Megas Comnenus with his brother David, the founder of the Empire of Trebizond and its ruler from 1204 until his death in 1222. The two brothers were the only male descendants of the Byzantine Emperor Andronikos I, who had been dethroned and killed in 1185, and thus claimed to represent the legitimate government of the Empire following the conquest of Constantinople by the Fourth Crusade in 1204. Although his rivals governing the Nicaean Empire succeeded in becoming the de facto successors, and rendered his dynastic claims to the imperial throne moot, Alexios' descendants continued to emphasize both their heritage and connection to the Komnenian dynasty by later referring to themselves as Megas Komnenos.
The Empire of Trebizond or the Trapezuntine Empire was one of the three successor rump states of the Byzantine Empire that existed during the 13th through to the 15th century. The empire consisted of the Pontus, or far northeastern corner of Anatolia, and portions of southern Crimea.