The Empire of Trebizond was a monarchy that flourished during the 13th through 15th centuries, comprising the far northeastern corner of Anatolia and the southern Crimea. Originally formed during a revolt against the usurpation of the imperial throne by the grandsons of Emperor Andronikos I Komnenos, Trebizond became a Byzantine Greek successor state established after the fall of the Byzantine Empire in the Fourth Crusade, along with the Empire of Nicaea and the Despotate of Epirus. The Emperors of Trebizond pressed their claim on the Imperial throne for decades after the Nicaean reconquest of Constantinople in 1261.