Mithras is an Indo-Iranian god adopted in the Roman Empire as the principle deity in the Mystery Cult which flourished in the 2nd and 3rd Centuries C.E. The Iranian Mithra was a god of compact (the literal meaning of his name), cattle herding, and the dawn light. Roman Mithras was a sun God, a bull killer and a cattle thief. He was the saviour of the sworn brothers of his cult. The cult is known primarily from it's archaeological remains Mithraism was an organisation of cells. Small autonomous groups of initiates, exclusively male, met for fellowship and worship in chambers of modest size called 'caves'. Traces of the cult have been found in virtually every quarter of the Roman Empire - it rarely attracted the upper classes. Astrology is thought have been important to the cult. (The Oxford Dictionary of Classical Myth and Religion, Oxford University Press, 2003, pp.356 - 357) I have also heard that the cross is a symbol of Mithras due to the sun being centred on the cross of the Zodiac and that his birthday was supposed to be November the 25th - he was considered a saviour figure and was also supposed to be born from a rock... (But I should research the things contained in this paragraph in order to be certain). It is hard to say anything certain about Mithraism, all of the evidence relating to it is open to interpretation as with any ancient religion... Hope that helps