"Mithras” is the Latin name of a Vedic god that the ancient Persians called “Mithra”, and in the Rig Veda is called “Mitra”. Mitra is one of the hundred plus names of Soma in the Rig Veda and means “the friend of all men”. Mitra is an extremely old God, whose name first appears in writing in a peace treaty between the Hittite empire and the Mitanni in approximately 1450BC, Mithra was often invoked in contracts and treaties. The Hittites and the Mitanni are both Indo-European peoples mentioned in the Old Testament Bible, where the Mitanni are called Hurrians, which Biblical, and other ancient sources, claimed to be the ancient worlds best horsemen and Charioteers.
During the rise of Zoroastrianism in Persia, the ancient cult of Mithra was suppressed for a short time, but rises again and is reincorporated into the Mazda religion of Persia. After Persia; was conquered by Alexander the Great; the cult of Mithra spreads deep into the Greek and later the Roman world and was extremely popular with warriors. For a short time, the Romans try to suppress the Mithras cult as a Persian subversion of the Roman people. The cult survives this persecution and begins to spread among all levels of the Roman Empires population, especially among the troops of the Roman legions, who spread it into the farthest reaches of the empire and beyond.
The cult of Mithras held its meetings and ceremonies, in small underground chambers called “Mithraeum”. These chambers could only accommodate perhaps 30 people; when the numbers of people became too large for that Mithraeum to hold, another Mithraeum was established.
The Mithras cult was strictly male in membership and like modern Secret Societies, the cults members were divided into a graduated hierarchy with 7 levels, only the highest grade of initiate could found a new Mithraeum. The ability of the Mithras cult to stay in small personal groups and still expand their total numbers was a key to their survival through any of the ancient persecutions. The cult of Mithras does not appear to be persecuted to any large extent by the official Christian Church, it seems they simply melted into Christianity.
Many modern Christians do not understand the tremendous influence Roman Mithraism had on early Christianity an influence that still exists today. Every Christmas; Christians, celebrate the birth of Mithras, on December 25, and every Sunday, they worship on Mithras sacred day. Most of the very old Christian Churches, in Europe and the Middle East, are built on top of even older Mithraeum. The Vatican’s Saint Peters Basilica, has an ancient Mithraeum in its basement. Literally and physically, the Soma God Mithras, and the ancient religion of Mithraism, are two of the main foundation stones of Christianity.
The birth of Mithras from the Cosmic Egg.
As Soma is born from the Golden Embryo.
A winged Mithras wrapped in a Serpent encircled with the Zodiac
Mithra and Haoma
There are many Solar, astrological and astronomical aspects to the Mithra myths, yet it is the Sacramental use of "Haoma" in the form of a special "Sacramental Wine" and the "Living Bread" by the various Mithra cults that is the real object of study by the Ambrosia Society.
The following is from the Encyclopedia Britannica (1991, vol. 26, pg. 789, Rites & Ceremonies):
“In Zoroastrianism haoma (Sanskrit soma, from the root su or bu, “to squeeze” or pound”) is the name given to the yellow plant, from which a juice was extracted and consumed in the Yasna ceremony, the general sacrifice in honor of all the deities. The liturgy of the Yasna was a remarkable anticipation of the mass in Christianity.” “Haoma was regarded by Zoroaster as the son of the Wise Lord and Creator (Ahura Mazda) and the chief priest of the Yasna cult. He was believed to be incarnate in the sacred plant that was pounded to death in order to extract its life-giving juice so that those who consumed it might be given immortality. He was regarded as both victim and priest in a sacrificial-sacramental offering in worship. As the intermediary between God and man, Haoma acquired a place and sacramental significance in the worship of Mithra (an Indo-Iranian god of light) in his capacity as the immaculate priest of Ahura Mazda with whom he was coequal. The Mithraic sacramental banquet was derived from the Yasna ceremony, wine taking the place of the haoma and Mithra that of Ahura Mazda. In the Mithraic initiation rites, it was not until one attained the status of the initiatory degree known as “Lion” that the neophyte could partake of the oblation of bread, wine, and water, which was the earthly counterpart of the celestial mystical sacramental banquet. The sacred wine gave vigor to the body, prosperity, wisdom, and the power to combat malignant spirits and to obtain immortality.”
As you can see the root theology of the Haoma is the same as the Christ, Haoma being the "Son of God" and "both victim and priest in a sacrificial-sacramental offering in worship." An impossibility must also be pointed out that "the liturgy of the Yasna was a remarkable anticipation of the mass in Christianity” in the quote above, now this either means Zoroaster was the worlds best prophet, or far more likely, that the Christian Mass is ulltimatly descended from the far older Yasna and Zoroaster. The Mithraic cult is another Indo-European Soma/Haoma cult carrying on their version of the ancient Sacramental use of Haoma. Ambrosia Society research has show, that the sacred wine and bread of the Mithras Communion was easily made with the Haoma plant, Amanita muscaria.
The Roman cult of Mithras died out with no known surviving texts, most stone inscriptions are dedications on donated statuary by individuals. Practices from Roman Mithraism survive in some Christian traditions to this day, including the Sacramental use of the "Haoma/Soma" as the Christian Eucharist.
The Rig Veda contains Hymns composed to Mitra and Mitra / Soma together.
These links provide you with more in depth information.