Crisis of the Third Century
By 258–260, the Empire had split into three competing states. There was the Gallic Empire, which included the Roman provinces of Gaul, Britannia and Hispania, and the Palmyrene Empire, with the eastern provinces of Syria Palaestina and Aegyptus. These became independent of the Italian Roman Empire proper, which stood between them. The crisis ended with the ascension of Diocletian in 284.