Which Byzantine successor state was founded in 1204 and survived until 1461?

The Empire of Trebizond was the Byzantine successor state founded in 1204 that survived until 1461. It emerged after the Fourth Crusade captured Constantinople and established the Latin Empire, breaking the Byzantine world into several rival Greek-led states.

The Komnenos brothers Alexios and David founded Trebizond on the southern Black Sea coast with support from their relative, Queen Tamar of Georgia. Its capital, Trebizond—modern Trabzon in Turkey—became a wealthy commercial center linking the Black Sea, the Caucasus, Persia and Anatolia.

Other Byzantine successor states included the Empire of Nicaea, the Despotate of Epirus and the Despotate of Morea. Nicaea eventually recaptured Constantinople in 1261 and restored the Byzantine Empire, but Trebizond remained politically independent. Its rulers continued to use the title of emperor and maintained a distinct court and diplomatic tradition.

The Ottoman conquest of Constantinople in 1453 did not immediately end Trebizond. Sultan Mehmed II conquered the city after a siege in 1461, making Trebizond the longest-lasting major Byzantine successor state. The small Principality of Theodoro, linked to Trebizond, survived in Crimea until 1475.