In 1776, Edward Gibbon described a fascinating sequence of events he calls the “ruin of Paganism” during the reign of Theodosius in his Decline and Fall of the Roman Empire. (Gibbon’s patrician, Enlightenment, classically conservative, modern, and rationalist biases are in full effect — but it’s a brilliant read.)
Gibbon wrote: “The ruin of the Pagan religion is described by the sophists as a dreadful and amazing prodigy, which covered the earth with darkness, and restored the ancient dominion of chaos and of night. . . a revolution, which raised those obscure victims of the laws of Rome to the rank of celestial and invisible protectors of the Roman empire.” He cites it as,”perhaps the only example of the total extirpation of any ancient and popular superstition; and may therefore deserve to be considered as a singular event in the history of the human mind.”
The third to wear the purple robes after Constantine declared himself a Christian was Constantine’s nephew, the last pagan emperor, Julian. Orphaned as a child, he raised as a Christian with his half-brother, consul of the east, Gallus. When he reached twenty, Julian rejected Christianity in a secret initiation into the Greek mysteries of Eleusis. He adopted neoplatonic philosophy, and worshiped the Greek pantheon. He hid his pagan devotion and feigned Christian worship for ten years, until he finally declared his paganism while waging a civil war against the Christian prince Constantinius. His victory revitalized paganism as well as religious toleration across the empire.