Council of Florence and the Orthodox–Catholic Union (1439)

Timeline

1. 1438–1439Florence · ItalyThreatened by plague, the Ferrara–Florence council that opened in 1438 relocated to Florence to continue. The Byzantine delegation debated theological differences such as the Filioque and papal primacy with Western theologians, paving the way for union negotiations.
2. 1439Florence Cathedral · TuscanyOn 6 July 1439, Eastern church representatives signed the Bull Laetentur Coeli in Florence, recognizing the Roman pope's chief position in the church and declaring the reunion of East and West, in exchange for Western military aid to Byzantium against the Ottoman Empire.
3. 1439–1440Constantinople · TurkeyThe union decree met strong opposition from monks and the laity in Constantinople, Moscow, Egypt, and elsewhere, and most Eastern patriarchates refused to recognize it. The Florentine union failed to unify the church, instead deepening the East–West schism and pushing the Eastern churches toward autonomy.