thumb|Double-faced Mithraic relief. [[Fiano Romano (Rome), 2nd to 3rd century CE (Louvre Museum).]]
thumb|Mithras killing the bull (; [[Louvre-Lens)]]
thumb|Rock-born Mithras and Mithraic artifacts ([[Baths of Diocletian, Rome)]]
Mithraism, also known as the Mithraic mysteries or the Cult of Mithras, was a Roman mystery religion focused on the god Mithras. Although inspired by Iranian worship of the Zoroastrian divinity (yazata) Mithra, the Roman Mithras was linked to a new and distinctive imagery, and the degree of continuity between Persian and Greco-Roman practice remains debatable.
The mysteries were popular among the Imperial Roman army from the 1st to the 4th century AD.
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 mithraea in the city of Rome.
Modern sources sometimes refer to the Roman religion as Roman Mithraism or Western Mithraism to distinguish it from Persian worship of Mithra.) is a form of Mithra, the name of an old, pre-Zoroastrian, and, later on, Zoroastrian, god
Excavations at Inveresk, Scotland in 2010 found two well-preserved altars to Mithras dated to 140 CE. The altars are believed to be from the Roman Empire's most northerly temple to Mithras.
Earliest cult locations
According to Roger Beck, the attested locations of the Roman cult in the earliest phase () are as follows:
The context is a prayer to the god Phoebus.
The cave is described as persei, which in this context is usually translated Persian. According to the translator J.H. Mozley it literally means Persean, referring to Perses, the son of Perseus and Andromeda,
Plutarch
The Greek biographer Plutarch (46–127 CE) says that "secret mysteries ... of Mithras" were practiced by the pirates of Cilicia, the coastal province in the southeast of Anatolia, who were active in the 1st century BCE: "They likewise offered strange sacrifices; those of Olympus I mean; and they celebrated certain secret mysteries, among which those of Mithras continue to this day, being originally instituted by them."
He mentions that the pirates were especially active during the Mithridatic wars (between the Roman Republic and King Mithridates VI of Pontus) in which they supported the king.
Dio Cassius
The historian Dio Cassius (2nd to 3rd century CE) tells how the name of Mithras was spoken during the state visit to Rome of Tiridates I of Armenia, during the reign of Nero. (Tiridates was the son of Vonones II of Parthia, and his coronation by Nero in 66 CE confirmed the end of a war between Parthia and Rome.) Dio Cassius writes that Tiridates, as he was about to receive his crown, told the Roman emperor that he revered him "as Mithras". Roger Beck thinks it possible that this episode contributed to the emergence of Mithraism as a popular religion in Rome.
Porphyry
thumb|Mosaic (1st century CE) depicting Mithras emerging from his cave and flanked by Cautes and Cautopates ([[Walters Art Museum)]]
The philosopher Porphyry (3rd–4th century CE) gives an account of the origins of the Mysteries in his work De antro nympharum (The Cave of the Nymphs).
According to Beck, Porphyry's De antro is the only clear text from antiquity which tells us about the intent of the Mithraic mysteries and how that intent was realized.
David Ulansey finds it important that Porphyry "confirms ... that astral conceptions played an important role in Mithraism."
here Mithras is given the epithet "the great god", and is identified with the sun god Helios.