From wikipedia: 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.[4] In this context, Mithraism has sometimes been viewed as a rival of early Christianity.[12]