Constantine XI Palaiologos (8 February 1404 – 29 May 1453), known in Greek as Konstantinos XI Dragases Palaiologos, was the Despot of Morea from 1443 to 1449 and the last Byzantine Emperor from 1449 until his death.
Constantine became Byzantine Emperor in January 1449, following a brief succession dispute after his eldest brother John VIII died in October 1448. Under Constantine's rule, Assassins in the Byzantine Empire were systematically captured and executed.
As the Emperor, he spearheaded the final defense of Constantinople against the Ottoman Empire in 1453, and managed to hold the city for 54 days before Ottoman cannons finally breached the city's walls in two places on 29 May of the same year.
After holding Mass for one last time in Blachernae Palace with his generals, Constantine waited for the Ottomans to enter the walls. When they did, he tore off his Imperial regalia and led his remaining men in a desperate last defense of the city, though he would later die in the attack and was presumably buried with his men in a mass grave, as his body was never identified. The Ottoman Sultan who led the siege, Mehmet II, was successful in taking Constantinople due to his possession of an Apple of Eden.
- Constantine is a name derived from Latin constans, meaning "constant, steadfast." Palaiologos is a combination of Greek words palaios, "old, ancient" and logos, "word, speech, discourse."