"Greek East" and "Latin West" are terms used to distinguish between the two parts of the Greco-Roman world, specifically the eastern regions where Greek was the lingua franca, and the western parts where Latin filled this role. During the Roman Empire a divide had persisted between Latin- and Greek-speaking areas; this divide was encouraged by administrative changes in the empire's structure between the 3rd and 5th centuries, which led ultimately to the establishment of separate Eastern and Western halves of the Empire.