The Persian Orient, then, exerted a dominant influence on the political institutions and artistic tastes of the Romans as well as on their ideas and beliefs. The propagation of the religion of Mithra, which always proudly proclaimed its Persian origin, was accompanied by a number of parallel influences of the
people from which it had issued. Never, not even during the Mohammedan invasions, had Europe a narrower escape from becoming Asiatic than when Diocletian officially recognized Mithra as the protector of the reconstructed empire.[[13]] The time when that god seemed to be establishing his authority over the entire civilized world was one of the critical phases in the moral history of antiquity. An irresistible invasion of Semitic and Mazdean conceptions nearly succeeded in permanently overwhelming the Occidental spirit. Even after Mithra had been vanquished and expelled from Christianized Rome, Persia did not disarm. The work of conversion in which Mithraism had failed was taken up by Manicheism, the heir to its cardinal doctrines, and until the Middle Ages Persian dualism continued to cause bloody struggles in the ancient Roman provinces.
Just as we cannot understand the character of the mysteries of Isis and Serapis without studying the circumstances accompanying their creation by the Ptolemies, so we cannot appreciate the causes of the power attained by the mysteries of Mithra, unless we go far back to their origin.
Here the subject is unfortunately more obscure. The ancient authors tell us almost nothing about the origin of Mithra. One point on which they all agree is that he was a Persian god, but this we should know from the Avesta even if they had not mentioned it. But how did he get to Italy from the Persian uplands?
Two scant lines of Plutarch are the most explicit document we have on the subject. He narrates incidentally that the pirates from Asia Minor vanquished
by Pompey in 67 performed strange sacrifices on Olympus, a volcano of Lycia, and practiced occult rites, among others those of Mithra which, he says, "exist to the present day and were first taught by them."[[14]] Lactantius Placidus, a commentator on Statius and a mediocre authority, also tells us that the cult passed from the Persians to the Phrygians and from the Phrygians to the Romans.[[15]]
These two authors agree then in fixing in Asia Minor the origin of this Persian religion that later spread over the Occident, and in fact various indications direct us to that country. The frequency of the name Mithradates, for instance, in the dynasties of Pontus, Cappadocia, Armenia and Commagene, connected with the Achemenides by fictitious genealogies, shows the devotion of those kings to Mithra.
As we see, the Mithraism that was revealed to the Romans at the time of Pompey had established itself in the Anatolian monarchies during the preceding period, which was an epoch of intense moral and religious unrest. Unfortunately we have no monuments of that period of its history. The absence of direct testimony on the development of Mazdean sects during the last three centuries before our era prevents us from gaining exact knowledge of the Parseeism of Asia Minor.
None of the temples dedicated to Mithra in that religion have been examined.[[16]] The inscriptions mentioning his name are as yet few and insignificant, so that it is only by indirect means that we can arrive at conclusions about this primitive cult. The only way to explain its distinguishing features in the Occident is to study the environment in which it originated.