The main challengers of the Albizzi family were the Medicis, first under Giovanni de' Medici, later under his son Cosimo de' Medici. The Medici controlled the Medici bank—then Europe's largest bank—and an array of other enterprises in Florence and elsewhere. In 1433, the Albizzi managed to have Cosimo exiled. The next year, however, saw a pro-Medici Signoria elected and Cosimo returned. The Medici became the town's leading family, a position they would hold for the next three centuries. Florence organized the trade routes for commodities between England and the Netherlands, France, and Italy. By the middle of the century, the city had become the banking capital of Europe, and thereby obtained vast riches. In 1439, Byzantine Emperor John VIII Palaiologos attended a council in Florence in an attempt to unify the Eastern and Western Churches. This brought books and, especially after the fall of the Byzantine Empire in 1453, an influx of scholars to the city. Ancient Greece began to be studied with renewed interest, especially the Neoplatonic school of thought, which was the subject of an academy established by the Medici.