Constantius II, 317–61, Roman emperor, son of Constantine I. When the empire was divided (337) at the death of Constantine, Constantius II was given rule over Asia Minor, Syria, and Egypt, while his brothers, Constans I and Constantine II, received other portions. He gained prestige by fighting successfully against the Persians. When in 350 the murder of Constans I threw the West into disorder, Constantius II defeated the usurping Magnentius, a German who had been a commander under Constans I, and became sole emperor. He delegated much power to his cousin Julian (Julian the Apostate) in Gaul. When a new dispute erupted with the Persians, Constantius ordered Julian to the East, but Julian’s men revolted and proclaimed (360) Julian emperor in the West. Constantius died in the Persian campaign in Cilicia, naming Julian as his successor. A confirmed Arian, Constantius vigorously repressed paganism and was involved in a struggle with St. Athanasius.

The Columbia Encyclopedia, Sixth Edition. Copyright © 2001 Columbia University Press.