IIN THE MIDDLE OF THE THIRD CENTURY, the Roman Empire faced internal turmoil and external attacks. Civil wars tore the empire apart, and barbarian groups migrated and marauded deep within the boundaries of the empire (see Chapter 6). Wars and invasions disrupted normal commerce and agriculture, the primary sources of tax revenues. The barracks emperors of the third century dealt with economic hardship by cutting the silver content of coins until money was virtually worthless. In the early fourth century, the emperor Diocletian (r. 284–305), who was born of low-status parents and had risen through the ranks of the military to become emperor, restored order, and the later emperor Constantine (r. 306–337) continued his work. How Diocletian, Constantine, and their successors responded to the problems facing the empire influenced later developments.