MITHRAS (MITHRES, MITHRA), a god, mentioned in Sanskrit and Old Persian documents and thus probably older than the separation of the Iranian stock from the Aryan invaders of India. (See INDIA, History; PERSIA, History.) History.—Although mentioned by Greek writers, particularly of Hellenistic date, as an important Persian deity, his history is ob scure. In Zoroastrianism as we know it, he is simply a Yazata, a kind of angel, a power of light who fights on the side of Ahura-Mazda. This warlike characteristic he seems always to have retained. But other evidence exists to show that his position remained higher than this would indicate. Names compounded of his (e.g., Mithradates) are common among Orientals of various epochs; his festival, the Mithrakana, (sixteenth day of the seventh month; both month and day were especially sacred to him) was brilliant, and modified forms of it survived to Muslim times.
His cult naturally spread with the Persian conquests, and in particular, he reached the Euphrates valley, where he was so long settled that several Greek and Roman writers speak of him as an Assyrian god. Another branch of his cult, of some impor tance for later developments, was established in Cilicia ; but for some reason he never penetrated to the western parts of Asia Minor till late times, about the beginning of the Christian era. Naturally, the concept of him was modified by contact with foreign cults, and in particular, he tended to be identified, or at least brought into close association with, the Sun. Perhaps as a result of the accretion of foreign worshippers, his cult took on, if it did not already possess, the form of a mystery, with more or less definite grades of initiation and ceremonials of purification, penance and so forth, appropriate to such a worship.
Mithraism was first transmitted to the Roman world during the st century B.C. by the Cilician pirates captured by Pompey. As late as the time of Augustus it was but little known in Roman territory, and gained a firm foothold in Italy only gradually, as a result of Rome's increasing hold upon Asia.
Towards the close of the 2nd century the cult had begun to spread rapidly through the army, the mercantile class, slaves and actual propagandists, all of which classes were largely com posed of Asiatics. It throve, especially among military posts, and in the track of trade, notably at ports. The German frontiers afford most evidence of its prosperity. Rome itself was a favour ite seat of the religion. From the end of the 2nd century the emperors encouraged Mithraism, because of the support which it afforded to the divine right of monarchs. The Persian belief that the legitimate sovereign reigned by the grace of Ormazd, whose favour was made manifest by the sending of the Hvarend, a kind of celestial aureole of fire, resulted in the doctrine that the sun was the giver of the Hvarend. Mithras, identified with Sol In victus, thus became the giver of authority and victory to the imperial house.
The beginning of the downfall of Mithraism dates from A.D. 275, when Dacia was lost to the empire. The aggression of Christianity also was now more effective. The emperors, however, favoured the cult, which was the army's favourite until Constantine de stroyed its hopes. The reign of Julian and the usurpation of Eugenius renewed the hopes of its devotees, but the victory of Theodosius (394) may be considered the end of its existence. It still survived in certain cantons of the Alps in the 5th century, and clung to life with more tenacity in its Eastern home.
Sources, Remains, Ritual.—The sources of present know ledge regarding Mithraism consist of the Vedas, the Avesta, the Pahlevi writings, Greek and Latin literature and inscriptions, and the cult monuments. The last include (a) some hundreds of sculptures, (b) numerous chapels, which are grottoes (spelaea) underground, or imitations thereof in masonry. The average grotto held from fifty to a hundred persons. The size of the sanctuaries, however, was compensated for by their number.