Or VII. (1390-1448), surnamed Palaeologus, East Roman emperor, son of Manuel II., succeeded to the throne in 1425. To secure protection against the Turks he visited the pope and consented to the union of the Greek and Roman churches, which was ratified at Florence in 1439. The union failed of its purpose, but by his prudent conduct towards the Ottomans he succeeded in holding possession of Constantinople, and in 1432 withstood a siege by Sultan Murad I.
See Turkey: History; and also E. Gibbon, The Decline and Fall of the Roman Empire, vi. 97-107 (ed. Bury, 1896); E. Pears, The Destruction of the Greek Empire, pp. 115-130 (1903).