Constantine XI Dragases Palaiologos or Dragaš Palaeologus (Greek: Κωνσταντῖνος Δραγάσης Παλαιολόγος, romanized: Kōnstantīnos Dragásēs Palaiológos; 8 February 1404 – 29 May 1453) was the last reigning Byzantine emperor from 23 January 1449 until his death in battle at the fall of Constantinople on 29 May 1453. Constantine's death marked the definitive end of the Eastern Roman Empire, which traced its origin to Constantine the Great's foundation of Constantinople as the Roman Empire's new capital in 330.
Constantine was the fourth son of Emperor Manuel II Palaiologos and Serbian noblewoman Helena Dragaš. Little is known of his early life, but from the 1420s onward, he repeatedly demonstrated great skill as a military general. Based on his career and surviving contemporary sources, Constantine appears to have been primarily a soldier. This does not mean that Constantine was not also a skilled administrator: he was trusted and favored to such an extent by his older brother, Emperor John VIII Palaiologos, that he was designated as regent twice during John VIII's journeys away from Constantinople in 1423–1424 and 1437–1440. In 1427–1428, Constantine and John fended off an attack on the Morea (the Peloponnese) by Carlo I Tocco, ruler of Epirus, and in 1428 Constantine was proclaimed Despot of the Morea and ruled the province together with his older brother Theodore and his younger brother Thomas. Together, they extended Roman rule to cover almost the entire Peloponnese for the first time since the Fourth Crusade more than two hundred years before and rebuilt the ancient Hexamilion wall, which defended the peninsula from outside attacks. Although ultimately unsuccessful, Constantine personally led a campaign into Central Greece and Thessaly in 1444–1446, attempting to extend Byzantine rule into Greece once more.
