The migration of Byzantine Greek scholars and other émigrés from Byzantium during the decline of the Byzantine Empire (1203–1453) and mainly after the fall of Constantinople to Muslims in 1453 until the 16th century, is considered by some scholars as key to the revival of Greek and Roman studies and subsequently in the development of the Renaissance. These emigres were grammarians, humanists, poets, writers, printers, lecturers, musicians, astronomers, architects, academics, artists, scribes, philosophers, scientists, politicians and theologians. They brought to Western Europe the far greater preserved and accumulated knowledge of their own (Greek) civilization. By 1500 there was a Byzantine Greek community of about 5,000 in Venice.

The lessons of Greek learning brought by Byzantine intellectuals changed the course of humanism and the Renaissance itself. While Greek learning affected all the subjects, history and philosophy in particular were profoundly affected by the texts and ideas brought from Byzantium.
Source: Renaissance