In 285 Diocletian, the Roman ruler from 284 to 305, divided the Roman state into two administrative regions to improve its response to multiple external threats. The western region included our geocultural provinces of Britannia, Gallia, Iberia, Carthaginia, Alpinia, and Latinia. The eastern region included Hellenia, Anatolia, central Levantia, and Egypt.
This division of the Roman state into western and eastern halves acknowledged important differences in language, culture, history, and geography that existed between the two. Perhaps unintentionally, it also organized and strengthened these differences.