Constantius II in Wikipedia

Flavius Julius Constantius (August 7, 317 – November 3, 361), commonly known as Constantius II, was Roman Emperor from 337 to 361. The second son of Constantine I and Fausta, he ascended to the throne with his brothers Constantine II and Constans upon their father's death. In 340, Constantius' brothers fought over the western provinces of the empire. Constans defeated his brother and ruled the west for a decade until the usurper Magnentius rebelled in 350. Constans was promptly assassinated, leaving Constantius as the only surviving son of Constantine. After defeating Magnentius at the Battle of Mursa Major and Mons Seleucus, his subsequent suicide left Constantius sole ruler of the empire. His military campaigns against Germanic tribes were successful: he defeated the Alamanni in 354, and campaigned across the Danube against the Quadi and Sarmatians in 357. In the east however, he fought the Sassanids for two decades with mixed success. Constantius elevated his cousin Julian to co-emperor in 355, but by spring 361 the two emperors were at war. However, Constantius died before the two could face each other in battle, naming Julian his successor...