Constantius II was one of the sons of Constantine the Great, the first Roman emperor to convert to Christianity. He ruled the eastern part of the Roman Empire from 337 to 361, after dividing it with his brothers Constantine II and Constans I. He was involved in many wars, both external and internal, and tried to impose his religious views on the empire.

Constantius was born on August 7, 317, in Sirmium, a city in modern Serbia. He was named Flavius Julius Constantius, after his grandfather, who had been a loyal general of Constantine’s father. He was raised as a Christian, and received a military education. In 324, he was made caesar, or junior emperor, by his father, who had defeated his rival Licinius and reunited the empire.

When Constantine died in 337, he left his three sons as co-emperors, each with a different territory. Constantius inherited the eastern provinces, including Greece, Asia Minor, Syria, and Egypt. He also oversaw the massacre of many of his relatives, who were potential rivals for power. He later accused his cousin Julian, who would become his successor, of being involved in the murder of his father.

Constantius faced several challenges during his reign. He had to deal with the threat of the Persian Empire under Shapur II, who invaded Roman territory several times. He also had to contend with rebellions and usurpations by various generals and governors, such as Magnentius, Vetranio, and Constantius Gallus. He fought several civil wars against them, and managed to defeat them all.

Constantius was also a fervent supporter of Arianism, a branch of Christianity that denied the full divinity of Jesus Christ. He opposed the Nicene Creed, which affirmed that Jesus was “of one substance” with God the Father. He convened several councils and issued several edicts to promote Arianism and suppress other forms of Christianity, especially Catholicism and paganism. He persecuted bishops and priests who resisted his authority, such as Athanasius of Alexandria and Hilary of Poitiers.

Constantius married three times. His first wife was a daughter of his uncle Julius Constantius, whose name is unknown. She died in childbirth in 338. His second wife was Eusebia, a noblewoman who supported him politically and culturally. She died in 360. His third wife was Faustina, another noblewoman who bore him a daughter named Flavia Maxima Constantia.

In 355, Constantius appointed his cousin Julian as caesar of the western provinces, after the death of his brother Constans. Julian proved to be a popular and successful ruler, who restored paganism and defended the empire against the Germanic tribes. In 360, Julian’s army proclaimed him as augustus, or senior emperor, against Constantius’ wishes. Constantius prepared to fight him, but died of a fever on November 3, 361, in Mopsuestia, a city in modern Turkey. He was buried in Constantinople (now Istanbul), in the Church of the Holy Apostles.