The Constantinian Dynasty officially began under Constantius I (r. 305-306 CE), when he became an Augustus of the Tetrarchy that ruled the Roman Empire. The dynasty really rose to prominence under Constantius’ son, Constantine the Great (r. 306-337).
Before the civil wars that brought Constantine to sole power in Rome, he began granting Christians tolerance and protections. At the beginning of his civil war, Constantine was a devotee of the Undying Sun (Sol Invictus), but around—and after—the Battle of Milvian Bridge (c. 312), Constantine seemed to believe that the Christian God was his personal patron.
When Constantine won the civil war in 324, he openly supported the Christian religion. He let Christians take prominent positions in the Roman Empire, and also brought in Christians as advisers to his imperial court. Though Constantine was a protector of Christianity, and showed deep interest in the religion, he remained for most of his life a catechumen, a person being instructed in the teachings of Christianity before baptism. Constantine was only fully converted and baptized when he was on his deathbed in 337, though even this is debated.
The Roman Empire passed to Constans, Constantine II, and Constantius II, but the bloody succession politics of Rome ensured that only Constantius II survived. All three of Constantine’s sons supported Christianity, but the last member of the Constantinian Dynasty would change that track record.
Flavius Claudius Julianus, better known as Julian the Apostate was the last of the Constantinian line. Emperor Julian ruled from 361-363. He was raised a Christian, but abandoned the religion around 361 for the traditional gods of the old Roman Empire. Alongside the public worship of the old gods, he also joined Mystery Religions such as the cults of Cybele and Mithras.
Though he rejected Christianity, Julian the Apostate did not renew violent persecution of Christians. Instead, he debated with the Christians and attempted to undermine their religion in more subtle ways. Julian used his knowledge of Christianity to attack Christianity’s weaker points, such as its connection to Judaism, and he undermined the influence of Christianity by implementing educational reform. Julian the Apostate, however, died in 363 in a war against Persia, and the emperors that followed him reinstated imperial support for Christianity.
- The Christians as the Romans Saw Them, by Robert Louis Wilken. New Haven: Yale University Press, 1984
- Introduction to medieval Europe, 300-1500, by Wim Blockmans and Peter Hoppenbrouwers. New York: Routledge, 2014.