Diocletian secured the empire's borders and purged it of all threats to his power. He separated and enlarged the empire's civil and military services, and reorganized the empire's provincial divisions, establishing the largest and most bureaucratic government in the history of the empire.
Diocletian also restructured the Roman government by establishing the Tetrarchy, a system of rule in which four men shared rule over the massive Roman Empire. The empire was effectively divided in two, with an Augustus and a subordinate Caesar in each half.
