John VIII Palaiologos
John VIII Palaiologos was the penultimate Byzantine emperor, the last to visit western Europe in search of aid, and the emperor who presided over the Council of Florence in 1438-1439, which produced a formal union of the Eastern and Western churches that came too late and was too unpopular to save the empire. Son of Manuel II, he became emperor in 1425. His reign was overshadowed by the renewed Ottoman menace under Murad II and then the young Mehmed II. The crusade of Varna in 1444, sparked partly by Byzantine diplomacy, was crushed by the Ottomans and proved to be the last serious western military effort on behalf of Byzantium. At the Council of Florence, John VIII personally attended and negotiated, accepting theological formulations acceptable to Rome in exchange for promises of military aid. He signed the union in 1439. Back in Constantinople, the union was fiercely rejected by the Orthodox clergy and people. The promised western aid never materialized in sufficient force. John died in October 1448. His brother Constantine XI inherited what remained - Constantinople alone - and four years later died defending the walls against Mehmed II's final assault.
- Lived: 1392 CE – 1448 CE
- Nationality: byzantine
- Roles: emperor, head_of_state, diplomat
