In the ancient Persian form Mithraism; Mithra is demi-god. He is viewed as the incarnated scion of Ahura-Mahzda, and Ahura-Mahzda is believed to be the source of all goodness, creator of the Universe, God of light, and source of life. Some scholars believe that in its original form; Mithraism was strictly monotheistic (perhaps the first truly monotheistic belief system), naming Ahura-Mahzda as the only deity. However, it is evident that if Mithraism was originally monotheistic, at some point in its evolution the belief system became dualistic. Another deity was set up as a counterpart to Ahura-Mahzda; forming a pantheon of sorts. This secondary deity was given the name Angra-Mainyu (whose name has given us the term anger). Angra-Mainyu was believed to be the “uncreated” source of evil in the world, whose agency was in diametric opposition to the light and life of Ahura-Mahzda, and that the drama of our lives on Earth was a reflection of the struggle between these two cosmic powers. This clearly defined dualism would be of great relevance to both Judaism and Christianity in the centuries to come.
In the later form of Mithraism, the Mithraism of the Roman Empire; the demi-god Mithra is again depicted to be in the same relationship to the high God. In this cultural context, the high God is given the name Sol Invictus, and is iconographically represented as the sun.
In both the ancient Persian form of Mithraism and the Roman form of Mithraism, the demi-god Mithra is seen as being sent to Earth by the deity responsible for the creation of the universe; in the former tradition Ahura-Mahzda, in the latter tradition Sol Invictus. In the Roman form of Mithraism the purpose of sending Mithra to Earth is for him to slay the “Primal Bull.” Upon slaying the bull, Mithra and Sol Invictus feast together from its flesh. This feast has the effect that afterwards Mithra and Sol become con-joined. They have dined together, they are now “as one.” They are joined together as one being with coextensive attributes each sharing the title Invictus, meaning unconquered. In Roman Mithraism this meal was considered to be the effective means of salvation for all human beings, and that by participating in a recreation of the sacred meal, through the rites of initiation the individual would become one with Mithra, therefore one with Sol Invictus, and thereby gaining a place in the heavenly paradise of the afterlife.
As I indicated earlier in my reference to Ulansey’s work; Persian Mithraism did not depict Mithra as the “bull-slayer.” The narrative from Persia is as follows: Mithra does not kill the primal-bull, rather Mithra and the bull are sent to Earth by Ahura-Mahzda, where they are assailed by the “evil-one.” Angra-Mainyu slays Mithra and the bull together, in an act of violence. Angra-Mainyu attempts to utterly destroy Mithra and the bull, but his efforts are frustrated by Ahura-Mazda. Through the power of the god of light, stalks of wheat, and the grape vine spring from the carcass of the bull. All manner of good things, and creatures flow from the bull to fill, and populate creation, and to be used by human. Ahura-Mahzda trasforms the violence of Angra-Mainyu into a new creation. New life springs from the bull, Mithra is restored, and returns to Ahura-Mahzda in heaven.
In my view there is no significant discrepancy between these two forms of the myth. In both versions Mithra is sent to Earth by a God of greater authority than himself. In both versions the bull is slain and its death is productive; both of new life, and of all good things on the Earth. In the Roman version the slaying of the bull is an explicit sacrifice. In the Persian version the intentionality of the sacrifice is implicit. The Roman version is not etiological, it does not address the origins of life on Earth, the Persian version is. The Roman version it is primarily a teleological myth having to do with human destiny, salvation, and the life of the immortal soul. The Persian version balances these two concerns. In the Persian account Mithra and the Bull are sent to Earth by the creator deity; their death is a vehicle by which the drama of life on Earth begins, making it a myth of origins. Their death, while being the result of violence perpetrated by the “evil-one” does not serve the interest of Angra-Mainyu, but does serve the interest of Ahura-Mahzda. Mithra of course does not die, because his soul is immortal and he returns to heaven. From the body of the bull comes an abundance of life, demonstrating that Ahura-Mahzda is greater, not only having the power to create goodness sui generous (in itself), but also having the power to bring good out of evil; making the fruit of the labor of Angra-Mainyu effectively nothing. This made Mithraism in Persia ostensibly dualistic, holding that Angra-Mainyu would eventually be overcome by Ahura-Mahzda; overcome in totality. This profound hope is apparent within the structure of myth itself. In both the Roman and the Persian versions of the death of the primal bull is emblematic of life; it is the creation of life itself, and also it is life restored. The principal actor in both versions of the narrative is God, the creator figured as either Ahura-Mahzda or Sol Invictus; respectively. Whether it is Mithra who kills the bull, or Angra-Mainyu; it does not matter. The slaying of the bull serves the purpose of the principal actor, Ahura-Mahzda/Sol Invictus, God of life, God of light, God of good.
And so I reiterate the assertion; what is significant and most consistent in the worship of Mithra from c. 700 BCE through c. 400 CE, from Rome to Persia, is the belief in the immortality of the soul, and the notion of personal salvation. In Mithraism, this theology underwent a profound development that it would have a lasting and significant impact on other faith traditions.