Mithraism, also known as the Mithraic mysteries, was a Roman mystery religion centered on the god Mithras. Although inspired by Iranian worship of the Zoroastrian divinity (yazata) Mithra, the Roman Mithras is linked to a new and distinctive imagery, with the level of continuity between Persian and Greco-Roman practice debated.[a] The mysteries were popular among the Imperial Roman army from about the 1st to the 4th century CE.[2]

Worshippers of Mithras had a complex system of seven grades of initiation and communal ritual meals. Initiates called themselves syndexioi, those "united by the handshake".[3] They met in underground temples, now called mithraea (singular mithraeum), which survive in large numbers. The cult appears to have had its centre in Rome,[4] and was popular throughout the western half of the empire, as far south as Roman Africa and Numidia, as far north as Roman Britain,[5](pp 26–27) and to a lesser extent in Roman Syria in the east.[4]

Mithraism is viewed as a rival of early Christianity.[6] In the 4th century, Mithraists faced persecution from Christians and the religion was subsequently suppressed and eliminated in the Roman empire by the end of the century.[7]

Numerous archaeological finds, including meeting places, monuments and artifacts, have contributed to modern knowledge about Mithraism throughout the Roman Empire.[8] 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.[5](p xxi) It has been estimated that there would have been at least 680 mithraea in the city of Rome.[9][full citation needed] No written narratives or theology from the religion survive; limited information can be derived from the inscriptions and brief or passing references in Greek and Latin literature. Interpretation of the physical evidence remains problematic and contested.[10]

The term "Mithraism" is a modern convention. Writers of the Roman era referred to it by phrases such as "Mithraic mysteries", "mysteries of Mithras" or "mysteries of the Persians".[1][11] Modern sources sometimes refer to the Greco-Roman religion as Roman Mithraism or Western Mithraism to distinguish it from Persian worship of Mithra.[1][12][13]

Double-faced Mithraic relief. Rome, 2nd to 3rd century CE ( Louvre Museum).
Mithras killing the bull ( c. 150 CE; Louvre-Lens)
Rock-born Mithras and Mithraic artifacts ( Baths of Diocletian, Rome)
Bas-relief of the tauroctony of the Mithraic mysteries, Metz, France.
Relief of Mithras as bull-slayer from Neuenheim near Heidelberg, framed by scenes from Mithras' life.
A Roman tauroctony relief from Aquileia ( c. 175 CE; Kunsthistorisches Museum, Vienna)
Mithras rising from the rock ( National Museum of Romanian History)
Mithras born from the rock ( c. 186 CE; Baths of Diocletian)
Drawing of the leontocephaline found at a mithraeum in Ostia Antica, Italy (190 CE; CIMRM 312)
Lion-headed figure from the Sidon Mithraeum (500 CE; CIMRM 78 & 79; Louvre)
Mithraic relief with original colors (reconstitution), ca. 140 CE–160 CE; from Argentoratum. Strasbourg Archaeological Museum.
A mithraeum found in the ruins of Ostia Antica, Italy.
Reconstruction of a mithraeum with a mosaic depicting the grades of initiation
Another dedication to Mithras by legionaries of Legio II Herculia has been excavated at Sitifis (modern Setif in Algeria), so the unit or a subunit must have been transferred at least once.
Mithras-Helios, with solar rays and in Iranian dress, [86] with Antiochus I of Commagene. ( Mt. Nemrut, 1st Century BCE)
Votive altar from Alba Iulia in present-day Romania, dedicated to Invicto Mythrae in fulfillment of a vow (votum)
Mithras and the Bull: This fresco from the mithraeum at Marino, Italy (third century) shows the tauroctony and the celestial lining of Mithras' cape.
Mosaic (1st century AD) depicting Mithras emerging from his cave and flanked by Cautes and Cautopates ( Walters Art Museum)
Augustan-era intaglio depicting a tauroctony ( Walters Art Museum)
4th-century relief of the investiture of the Sasanian king Ardashir II. Mithra stands on a lotus flower on the left holding a barsom. [86]
Bas-relief depicting the tauroctony. Mithras is depicted looking to Sol Invictus as he slays the bull. Sol and Luna appear at the top of the relief.
Sol Invictus from the Archaeological Museum of Milan (Museo archeologico)
Unusual tauroctony at the Brukenthal National Museum
Sol and Mithras banqueting with Luna and the twin divinities Cautes and Cautopates, his attendants (side  B of a double-sided Roman marble relief, 2nd or 3rd  century CE)
Mithraic altar depicting Cautes riding a bull (Sibiu/Hermannstadt, Romania)