Deaths on May 29

Constantine XI Palaiologos, Byzantine emperor (b. 1404)

Constantine XI Dragases Palaiologos or Dragaš Palaeologus (Greek: Κωνσταντῖνος Δραγάσης Παλαιολόγος, Kōnstantînos Dragásēs Palaiológos; 8 February 1405 – 29 May 1453) was the last Byzantine emperor, reigning from 1449 until his death in battle at the Fall of Constantinople in 1453. Constantine's death marked the end of the Byzantine Empire, which traced its origin to Constantine the Great's foundation of Constantinople as the Roman Empire's new capital in 330. Given that the Byzantine Empire was the Roman Empire's medieval continuation, with its citizens continuing to refer to themselves as Romans, Constantine XI's death and Constantinople's fall also marked the definitive end of the Roman Empire, founded by Augustus almost 1,500 years earlier.

Constantine was the fourth son of Emperor Manuel II Palaiologos and Helena Dragaš, the daughter of Serbian ruler Konstantin Dejanović. Little is known of his early life, but from the 1420s onward, he is repeatedly demonstrated to have been a skilled general. Based on his career and surviving contemporary sources, Constantine appears to primarily have been 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 Byzantine 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.

In 1448, John VIII died without children, and as his favored successor, Constantine was proclaimed emperor on 6 January 1449. Constantine's brief reign would see the emperor grapple with three primary concerns. First, there was the issue of an heir, as Constantine was also childless. Despite attempts by Constantine's friend and confidant George Sphrantzes to find him a wife, Constantine ultimately died unmarried. The second concern was the religious disunity within what little remained of his empire. Constantine and his predecessor John VIII both believed a union between the Orthodox and Catholic Churches was needed to secure military aid from Catholic Europe, but much of the Byzantine populace opposed the idea. Finally, the most important concern was the growing Ottoman Empire, which by 1449 completely surrounded Constantinople. In April 1453, the Ottoman Sultan Mehmed II laid siege to Constantinople with an army perhaps numbering as many as 80,000 men. Even though the city's defenders may have numbered less than a tenth of the sultan's army, Constantine considered the idea of abandoning Constantinople unthinkable. The emperor stayed to defend the city and on 29 May, Constantinople fell. Constantine died the same day. Although no reliable eyewitness accounts of his death survived, most historical accounts agree that the emperor led a last charge against the Ottomans and died fighting.

Constantine was the last Christian ruler of Constantinople, which alongside his bravery at the city's fall cemented him as a near-legendary figure in later histories and Greek folklore. Some saw the foundation of Constantinople (the New Rome) under Constantine the Great and its loss under another Constantine as fulfillment of the city's destiny, just as Old Rome had been founded by a Romulus and lost under another, Romulus Augustulus. He became known in later Greek folklore as the Marble Emperor (Greek: Μαρμαρωμένος Βασιλεύς, romanized: Marmaromenos Vasilias, lit. 'Emperor/King turned into Marble'), reflecting a popular legend which endured for centuries that Constantine had not actually died, but had been rescued by an angel and turned into marble, hidden beneath the Golden Gate of Constantinople awaiting a call from God to be restored to life and reconquer both the city and the old empire.