born Feb. 9, 1404, Constantinople
died May 29, 1453, Constantinople
Last Byzantine emperor (1449–53), sometimes called Constantine XII because of the erroneous notion that Constantine Lascaris was crowned in 1204.
He became emperor when his brother John VIII Palaeologus died childless, but he faced a losing battle against the Ottoman Turks, who were directing all their resources toward the capture of Constantinople. He acknowledged the obedience of the Greek church to Rome in order to secure help from the West, but in vain. He was killed fighting at the walls of Constantinople as the Turks broke through.