Solar pantheism, which grew up among the Syrians of the Hellenistic period as a result of the influence of Chaldean astrolatry, imposed itself upon the whole Roman world under the empire. Our very rapid sketch of the constitution of that theological system shows incidentally the last form assumed by the pagan idea of God. In this matter Syria was Rome's teacher and predecessor. The last formula reached by the religion of the pagan Semites and in consequence by that of the Romans, was a divinity unique, almighty, eternal, universal and ineffable, that revealed itself throughout nature, but whose most splendid and most energetic manifestation was the sun. To arrive at the Christian monotheism[89] only one final tie had to be broken, that is to say, this supreme being residing in a distant heaven had to be removed beyond the world. So we see once more in this instance, how the propagation of the Oriental cults levelled the roads for Christianity and heralded its triumph. Although astrology was always fought by the church, it had nevertheless prepared the minds for the dogmas the church was to proclaim. * * * * * {135} PERSIA. The dominant historical fact in western Asia in ancient times was the opposition between the Greco-Roman and Persian civilizations, which was itself only an episode in the great struggle that was constantly in progress between the Orient and the Occident in those countries. In the first enthusiasm of their conquests, the Persians extended their dominion as far as the cities of Ionia and the islands of the AEgean Sea, but their power of expansion was broken at the foot of the Acropolis. One hundred and fifty years later, Alexander destroyed the empire of the Achemenides and carried Hellenic culture to the banks of the Indus. After two and a half centuries the Parthians under the Arsacid dynasty advanced to the borders of Syria, and Mithradates Eupator, an alleged descendant of Darius, penetrated to the heart of Greece at the head of his Persian nobility from Pontus. After the flood came the ebb. The reconstructed Roman empire of Augustus soon reduced Armenia, Cappadocia and even the kingdom of the Parthians to a kind of vassalage. But after the middle of the third century the Sassanid dynasty restored the power of Persia and revived its ancient pretensions. From that time until the triumph of Islam it was one long {136} duel between the two rival states, in which now one was victorious and now the other, while neither was ever decisively beaten. An ambassador of king Narses to Galerius called these two states "the two eyes of the human race."[1]