Greeks in their fanciful way made a Harpocrates, the God of Silence, misunderstanding the symbol of the finger in the mouth, which for the Egyptians meant merely childhood. As we have seen, the Osirian cult and that of Serapis, grafted on it in the time of the Ptolemies, made popular the symbol of the cross long before Christianity, and prepared for the latter religion in many other ways. Perhaps its closest counterpart, however, was its most tenacious rival, the worship of the Persian Sun-God Mithra, first introduced into Rome in the time of Pompey, whose troops received it from the Cilician pirates, the débris of the army of Mithridates, whom he conquered and enlisted in the Roman service. Mithra being the most august of all the Gods of war, his worship became the special religion of the Roman army. Apart from its promise of immortality, its fascination lay in its elaborate initiations, baptisms, probations, sacraments, and mysteries, which were kept at a higher level of moral stringency than those of almost any of the competing cults. The God was epicene or bisexual, having a male and a female aspect; and there seems to have been no amorous element in his myth at the Christian period. Unless it be decided that such rituals had prevailed all over the East, the Christian eucharist must be held to have been a direct imitation of that of Mithraism, which it so closely resembled that the early Fathers declared the priority of the rival sacrament to be due to diabolic agency. But the Christian rite, as we have seen, had old Palestinian roots, going back to sheer human sacrifice. The Mithraist ritual, indeed, appears to have been the actual source of part of the Christist mystery-play, inasmuch as Mithra, whose special epithet was "the Rock," was liturgically represented as dead, buried in a rock tomb, mourned over, and raised again amid rejoicing. For the Mithraists also the sign of the cross, made on the forehead, was the supreme symbol; and it was mainly their cult which established the old usage of calling the Sun-day, the first of the week, "the day of the Lord," Mithra as the Sun being the first of the seven planetary spirits on whose names the week was based. In the third century, the chief place of the cult in the empire was on the Vatican mount at Rome; and there it was that Christian legend located the martyrdom of Peter, who, as we have seen, was assimilated to Mithra both in name and in attributes. [20]