Mithraic Mysteries were a mystery religion practised in the Roman Empire from about the 1st to 4th centuries AD. The name of the Persian godMithra (proto-Indo-Iranian Mitra), adapted into Greek as Mithras, was linked to a new and distinctive imagery. Writers of the Roman Empire period referred to this mystery religion by phrases which can be anglicized as Mysteries of Mithras or Mysteries of the Persians; modern historians refer to it as Mithraism, or sometimes Roman Mithraism. The mysteries were popular in the Roman military.
Worshippers of Mithras had a complex system of seven grades of initiation, with ritual meals. Initiates called themselves syndexioi, those “united by the handshake”. They met in underground temples (called mithraea), which survive in large numbers. The cult appears to have had its centre in Rome.
Numerous archeological finds, including meeting places, monuments, and artifacts, have contributed to modern knowledge about Mithraism throughout the Roman Empire. The iconic scenes of Mithras show him being born from a rock, slaughtering a bull, and sharing a banquet with the god Sol (the Sun). About 420 sites have yielded materials related to the cult. Among the items found are about 1000 inscriptions, 700 examples of the bull-killing scene (tauroctony), and about 400 other monuments. It has been estimated that there would have been at least 680-690 Mithraea in Rome. No written narratives or theology from the religion survive, with limited information to be derived from the inscriptions, and only brief or passing references in Greek and Latin literature.
Interpretation of the physical evidence remains problematic and contested.
The Romans themselves regarded the mysteries as having Persian or Zoroastrian sources. Since the early 1970s, however, the dominant scholarship has noted dissimilarities between Persian Mithra-worship and the Roman Mithraic mysteries, and the mysteries of Mithras are now generally seen as a distinct product of the Roman Imperial religious world. In this context, Mithraism has sometimes been viewed as a rival of early Christianity.