Flavius Julius Constantius, the second son of Constantine the Great and his second wife Fausta, was born in 317 A.D. And was given the rank of Caesar in 324, soon after the defeat of his father's rival Licinius. On the division of the empire at the death of Constantine, Constantius II received all the eastern territories from Asia Minor to Cyrenaica, and two years later, in 339, he also acquired Thrace. Following the death of his brother Constans in 350, Constantius marched against the usurper Magnentius and gained a decisive victory over him in September of 351. By 353, Magnentius was finally destroyed, and Constantius spent the next few years campaigning on the Danube frontier. War with Persia, however, necessitated his return to the east in 359, but early in the following year he received word that his cousin Julian had been proclaimed emperor by his troops at Paris. After some delay due to the Persian war, Constantius set out for the west, but while advancing through Cilicia he fell ill with fever and died at Mopsucrene in 361, thus leaving Julian master of the Roman world.