The evolution of the divine Mithras from his place in the distant Eastern past to his position of the bull-slayer in his Roman mysteries is a long, complex and largely unknown process.
Among ancient Indo-Iranian peoples, Mithras was the god of light, truth and integrity. In the Vedic literature of ancient India, Mitra is allied with the god of heaven; and in Persia he was associated with Ahura Mazda, the wise lord. According to the Avesta Mithra was the champion of truth, a warrior against falsehood. He is called “the lord of wide pastures”; he provided cattle, prosperity and life.
The ancient priesthood of the Magi developed the religious beliefs surrounding Mithras further. As the Magi, and their worship, spread west so did that of Mithras. Even as early as the 1st century BC pirates of south eastern Asia Minor were said, by Plutarch, to be practicing the mysteries of Mithras.
The Mithraic mysteries became a Roman phenomenon that flourished from the 2nd century AD. They were a mysteries for men. In particular soldiers, sailors and imperial officers were drawn to the divine warrior of truth, light and justice. Emperors too favoured his worship.
His sanctuaries were called Mithraea, and large numbers of them have been found. They appear particularly in the frontier provinces where Roman Legions were stations, as well as in ports and major cities. The sanctuaries themselves were designed to mimic caves. In these sanctuaries, the devotees of Mithras took part in various purifications, initiatory rites, and ceremonial meals.
According to one Christian writer, Tertullian, Mithraic initiates underwent ordeals and tests of valour, they were washed in water, and a seal was placed on their foreheads. Another writer, Justin Martyr, claimed initiates took bread and water (or water and wine) to symbolise the body and blood of the bull, as part of a holy meal.
The rituals were intended to bring the salvation and transformation of those involved. Inscriptions speak of rebirth and creation (or re-creation). Texts further suggest that the new life of the initiate was experienced in an ascent of the soul to the realms of the divine. This re-creation was not limited to the initiates but was applied to the cosmos as a whole. Mithraic monuments show the sacrifice of the bull was the moment of creation and life, grain is seen to be sprouting either from the bull’s tail or the wound itself.
There were 7 progressive stages of initiation: first the Raven (Corax), then the Bridegroom (Nymphus; or the Occult, Cryphius), next the Soldier (Miles), the Lion (Leo), then the Persian (Perses), the Courier of the Sun (Heliodromous) and finally the Father (Pater). This matches with archaeological evidence from the Mithraeum of Felicissimus at Ostia where the floor has seven stations, each decorated with symbols appropriate to each stage of initiation. Another has seven stations marked out by seven arcs; another has a mosaic floor depicting seven gates.
Much of our knowledge on Mithraic mythology comes from archaeological monuments. One, from Heddernheim, Germany, is a double side relief on a pivot so it could be rotated. On one side Mithras kills the bull. As the bull dies three heads of grain grow from its tail. Mithras is shown wearing a Persian cap and his cloak flies out behind him and a raven, the messenger of the sun perches on the cloak. On the other side of the relief torchbearers are shown; Cautes (with torch up) and Cautopates (with torch down) which symbolising the rising and setting of the sun. Above Mithras is a border with the 12 signs of the zodiac. The border acts as the ceiling of the cave, because the cave was a microcosm of the universe, a firmament of heaven.
We have scenes from all through Mithras’ life. He was born from a rock at the time of the winter solstice, he shoots an arrow at a rock to open a spring, and he emerges from a tree. He is shown carrying the bull to be sacrificed, he meets the Sun (Helios, Sol) who kneel before him; they shake hands and ride off together in the chariot of the Sun. Mithras and the Sun also share a meal in a cave.
The interpretation of all this evidence is controversial. There are clear Persian motifs (in Mithras’ dress and the grade of initiation). The link to the zodiac and heavens is obvious; Mithras himself has been linked to the constellation Perseus, poised with a dagger above Taurus. However there are little certainties about Mithras and the Roman cult for him. It was extremely popular. This is attested by the archaeological record and by literary accounts.