What is Greek East and Latin West?

Greek East and Latin West are terms used to distinguish between the two parts of the Greco-Roman world and of Medieval Christendom, specifically the eastern regions where Greek was the lingua franca and the western parts where Latin filled this role. Greek was spread in the context of Hellenization, whereas Latin was the official aministrative language of Roman Empire. In the east, where both languages co-existed within the Roman administration for several centuries, the use of Latin ultimately declined as the role of Greek was further encouraged by administrative changes in the empire's structure between the 3rd and 5th centuries, which led to the split between the Eastern Roman Empire and the Western Roman Empire. This Greek-Latin divide continued with the East-West schism of the Christian world during the Early Middle Ages.