In what year did the Byzantine Empire fall?

The Byzantine Empire is conventionally said to have fallen in 1453.

That was the year Ottoman Sultan Mehmed II captured Constantinople, the empire’s capital and last major stronghold. The final siege began on 6 April and ended on 29 May 1453, when Ottoman forces breached the city’s defenses. The Byzantine emperor Constantine XI Palaiologos died during the final fighting.

By that point, the empire had been severely weakened by civil wars, economic decline, territorial losses, and the Fourth Crusade’s capture and sack of Constantinople in 1204. In 1261, the Byzantines recovered the city, but the restored empire never regained its earlier power. By 1453, Byzantine territory was largely confined to Constantinople and a few remaining possessions.

Some Greek successor states continued after the fall of Constantinople, most notably the Empire of Trebizond, which was conquered by the Ottomans in 1461. Even so, 1453 is the accepted answer because the capture of Constantinople ended the continuous Byzantine imperial state and is the standard date used by quizmasters and historians.