Byzantine emperor (1341-1391).
John V was born on 18 June 1332, the son of Emperor Andronikos III Palaiologos and Anne of Savoy. He acceded to the throne as a child of nine but did not exercise power until 1354. By that time the Byzantine Empire had been devastated by a series of protracted civil wars and reduced to little more than Thrace and the city of Constantinople (mod. Istanbul, Turkey). Worse still, the Ottoman Turks had captured the strategically vital city of Gallipoli (mod. Gelibolu, Turkey), thus gaining a foothold on the European side of the Bosporus from which to begin their conquest of the Balkans.
On the advice of Amadeus VI, count of Savoy, who in 1366 had recaptured Gallipoli, John decided to open negotiations with the papacy. He offered to end the schism between the Eastern and Western churches, if the pope would preach a crusade against the empire’s Turkish enemies. In 1369, John himself led a delegation to Rome, where he declared himself converted to the Roman Catholic faith and heard mass with the pope. Little practical help reached Constantinople as a result of John’s visit, however, and the Ottoman victory over the Serbs at the Marica in 1371 forced the emperor to change his policy.
By 1373 John had become a vassal of Sultan Murad I, paying tribute and providing troops to serve in the Ottoman army. John’s rule was also destabilized by rebellions by his son Andronikos IV (d. 1385) in 1376-1379 and by his grandson John VII (d. 1408) in 1390. On his death John was succeeded by his second son, Manuel II.