The Roman deity Mithras appears in the historical record in the late 1st century A.D., and disappears from it in the late 4th century A.D. Unlike the major mythological figures of Graeco-Roman religion, such as Jupiter and Hercules, no ancient source preserves the mythology of the god. All of our information is therefore derived from depictions on monuments, and the limited mentions of the cult in literary sources.

The temples of Mithras were always an underground cave, featuring a relief of Mithras killing the bull. This “tauroctony”, as it is known today, appears in the same format everywhere, but with minor variations. Other standard themes appear in the iconography.

The cult was all male. There were seven degrees of initiation. Different ritual meals were associated with each stage.

(www.tertullian.org)