Imperio latino
The Latin Empire, established by the Crusaders in Constantinople, had poor control over former Byzantine territory, and Greek successor states of the Byzantine Empire sprang up in Epirus, Trebizond, and Nicaea. Trebizond had broken away as an independent state a few weeks before the fall of Constantinople. Nicaea, however, was the closest to the Latin Empire and was in the best position to attempt to re-establish the Byzantine Empire.