The Roman Empire fell in A.D. 476. For almost six hundred years thereafter, Rome and Constantinople —the seats of the Western and Eastern branches of Christianity, respectively—vied with each other for dominance. Each wanted to become the single leader of a unified Christian Church. Ultimately, their power struggles and irreconcilable theological differences resulted in a permanent schism between the two factions. Thus, in 1054, the Christian Church split into the Roman Catholic (or Latin) Church, under the pope in Rome, and the Greek Orthodox Church, led by the bishop in Constantinople (now Istanbul ).

The Greek or Eastern empire became known as the Byzantine Empire, after Byzantium, a Greek colony once located in the region. Both the Western and Eastern empires shared a common classical Greek influence. In contrast to the Christian West, however, many of the Eastern empire's dominant cultural...