Constantius II

Constantius became Augustus alongside his brothers Constantine II and Constans on 9 September 337, immediately ordering the massacre of his father-in-law, an uncle, and several cousins. The three brothers carved up the empire, Constantius taking the east, where he spent a decade locked in costly, inconclusive war with Persia. By 340 his brother Constantine was dead; by 350 Constans had been overthrown and killed by the usurper Magnentius. Constantius crushed Magnentius at Mursa Major in 351 and Mons Seleucus in 353, the usurper dying by suicide, leaving Constantius sole ruler. He elevated his cousin Gallus to Caesar in 351, then had him executed three years later for violent corruption, before promoting Gallus's half-brother Julian in 355. Julian claimed the rank of Augustus in 360, forcing Constantius to march west for yet another civil war, but he fell ill and died of fever on 3 November 361 in Mopsuestia, allegedly naming Julian his successor.