Principality of Theodoro
The Empire of Trebizond, which had split away from the Byzantine Empire just weeks before Constantinople was taken by the Crusaders in 1204, became the last remnant and last de facto successor state to the Byzantine Empire. Efforts by the Emperor David to recruit European powers for an anti-Ottoman crusade provoked war between the Ottomans and Trebizond in the summer of 1461. After a month-long siege, David surrendered the city of Trebizond on 14 August 1461. The Empire of Trebizond's Crimean principality, the Principality of Theodoro (part of the Perateia), lasted another 14 years, falling to the Ottomans in December 1475.