Although Mithraism, the most popular religion among the soldiers in the Roman legions, became Christianity's greatest rival in the early centuries of the church, it was not, as is often incorrectly cited, a Christian heresy. While it is true that the worshippers of the Persian god Mithras spoke of the adoration of their deity by a group of shepherds at his miraculous birth, observed a baptismal ritual that must be observed by those who wished to follow him, participated in a communal meal of bread and water which resembled the Eucharist, and celebrated his birthday on December 25, Mithraism had been established throughout the Persian Empire at least 500 years before the birth of Jesus Christ in 6 B.C.E. Mithraism had been spread throughout the then-known world by a group of magi, who preached an apocalyptic scenario in which Mithras, greatly associated with solar symbolism, would return at the end of a 7,000-year cycle to renew the world and to reestablish his earthly reign.
In Rome, Mithras had appeal to both the foot soldier and his ranking officers. Mithraism was a macho religion for men only—no women allowed. After baptismal rites had been conducted, the rugged legionnaires passed through graded ranks, such as Crow, Soldier, Lion, Courtier of the Sun, and, ultimately, Father. Boys as young as seven could begin their initiation as Crow, and neither military rank nor class distinctions differentiated those who followed Mithras. Those who declared themselves to be practicing Mithraists were valued as disciplined and temperate soldiers who had formed an unbreakable bond with their fellow worshippers. And those men who faced death in battle were assured that the rites of Mithras would guide them securely into a peaceful afterlife.
The powerful effects of Emperor Constantine's (d. 337) conversion to Christianity in the fourth century had a great influence on vast numbers of the Roman legions, and thousands of soldiers followed his example and converted to the teachings of Jesus of Nazareth (c. 6 B.C.E.–c. 30 C.E.) and the Christian Church. Mithraism gradually faded into obscurity by the end of the fourth century, retaining only small pockets of followers scattered throughout what had once been the Persian Empire.
Clifton, Chas S. Encyclopedia of Heresies and Heretics. New York: Barnes & Noble, 1998.
Fox, Robin Lane. Pagans and Christians. New York: Alfred A. Knopf, 1989.
Spence, Lewis. Encyclopedia of Occultism. New Hyde Park: N.Y.: University Books, 1960.