In February 1438 the Byzantine Emperor John VIII Paleolo-gus arrived in Florence with a retinue of 700 Greeks and the head of the Orthodox Church, the Patriarch Joseph II. As well as the Greek delegation, deputations arrived from Trebizond, Russia, Armenia, Cairo, and Ethiopia. As with many Renaissance transactions ostensibly concerned with religion, this momentous official meeting between east and west had profound political and cultural implications.

John VIII had proposed a union between the eastern and western branches of Christendom as the only realistic way to prevent the collapse of the Byzantine Empire and the capture of Constantinople in the face of the inexorable rise of the Ottoman Empire. The pope was eager to unify the two churches as a way of extending his own political power throughout Italy, as well as avoiding the more pressing internal disputes that had dogged him throughout the Council of Basle.

Away from official council business, delegates enthusiastically explored each other's intellectual and cultural achievements.

The Greeks admired the architectural achievements of Brunel-leschi, the sculpture of Donatello, and the frescoes of Masaccio and Fra Angelico.

The Florentines marvelled at the extraordinary collection of classical books that John VIII and his scholarly retinue had brought with them from Constantinople. These included beautiful manuscripts of Plato, Aristotle, Plutarch, Euclid, and Ptolemy and other classical texts which were 'not accessible here' in Italy according to one envious scholar.

The Egyptian delegation presented the Pope with a loth-century Arabic manuscript of the Gospels translated from a Coptic original, and the Armenian delegation left behind 13th-century illuminated manuscripts on the Armenian Church that reflected its mixed Mongol, Christian, and Islamic heritage.

The Ethiopian delegation also circulated elegant 15th- century Psalters written in Ethiopic and used in churches throughout northern and eastern Africa.

On 6 July 1439 the Decree of Union was finally signed between the two churches. It rejoiced that 'the wall which separated the Eastern Church and the Western Church has been destroyed, and peace and concord have returned through "Christ the corner-stone who has made the two one" (Eph. 2:20,14), the most powerful bond of peace joining them and attaching them by a treaty of perpetual unity'.

The rejoicing was short- lived. Back in Constantinople, the union was firmly rejected by the populace, stirred up by hardline orthodox members of the Eastern Church, while the Italian states demonstrated their reluctance by consistently refusing to provide military aid to assist the Byzantines in their struggle against the Ottomans. With the fall of Constantinople to Mehmed II in May 1453, the union came to a bloody and ignominious end.