The worship of the Indo-Iranian god of light Mithra (in Sanskrit Mitra). The religion originated in Persia from where it spread to Asia minor and then to Rome and much of the Roman empire. It was the chief rival to Christianity. The Avestan hymns, particularly in Yasht, depict Mithra as the god of heavenly light, all-seeing, protector of the virtuous in this world and the next and, most importantly, the foe of the powers of evil and darkness.
The exact time of the emergence of Mithraism in the West is indeterminate, but late in the first century CE it had secured a firm foothold, by which time it had accumulated much in the way of additions in iconography, Chaldean astrology, and sophisticated mysteries.
Not a great deal is known for certain about the Mithraic mysteries. It is believed that there were seven degrees of initiation for the adept; initiation was open to men of all ages, but closed to women. At each stage of initiation, the candidate had to undergo certain ordeals, for instance that of Miles involved branding the forehead. Mithraism had no complex hierarchical structure although the bigger centers had a pater patrum, similar to the Christian bishop.
Helena P. Blavatsky suggests that “. . . the Church has preserved in her most sacred rites the ‘star-rites’ of the Pagan Initiates. In the pre-Christian Mithraic Mysteries, the candidate who overcame successfully the ‘twelve Tortures’ which preceded the final Initiation, received a small round cake or wafer of unleavened bread, symbolizing in one of its meanings, the solar disc, and known as the manna (heavenly bread). . . . A lamb, or a bull even, was killed, and with the blood the candidate had to be sprinkled, as in the case of the Emperor Julian’s initiation” (CW XIV:319-20 fn.).