C. Aurelius Valerius Diocletian was born in Dalmatia about 245 A.D. having risen from the ranks of the roman army; he was given the governorship of Moesia (southern Europe). Following the death of Numerian, Diocletian was proclaimed emperor by the army and in 285 became sole emperor after the assassination of Carinus. Diocletian soon realized that the government and defense of such a vast empire was too great a task for one man, so he placed Maximianus in charge of the western half of the empire, while Diocletian administered the eastern provinces. In 293 A.D. the system was further extended by the appointment of two Caesars, Constantius and Galerius, each having several provinces to govern and defend. This organization became known as the first tetrachy. In 305 Diocletian and Maximianus, by prior agreement, abdicated. Galerius and Constantius who were then raised to augusti took their places. In his life, Diocletian was a competent general but he was far more distinguished as a statesman and reformer than as a soldier. During his rule he introduced numerous reforms, such as the tetrachy, which completely transformed the character of the empire. He also introduced a new monetary system, periodically striking a new coin.