There was one form of religion with which the Jews came in contact which was comparatively pure; and this was the religion of Persia, the loftiest form of all Pagan beliefs. The Persians were an important branch of the Iranian family. "The Iranians were the dominant race throughout the entire tract lying between the Suliman mountains and the Pamir steppe on the one hand, and the great Mesopotamian valley on the other." It was a region of great extremes of temperature,--the summers being hot, and the winters piercingly cold. A great part of this region is an arid and frightful desert; but the more favored portions are extremely fertile. In this country the Iranians settled at a very early period, probably 2500 B.C., about the time the Hindus emigrated from Central Asia to the banks of the Indus. Both Iranians and Hindus belonged to the great Aryan or Indo-European race, whose original settlements were on the high table-lands northeast of Samarkand, in the modern Bokhara, watered by the Oxus, or Amon River. From these rugged regions east of the Caspian Sea, where the means of subsistence are difficult to be obtained, the Aryans emigrated to India on the southeast, to Iran on the southwest, to Europe on the west,--all speaking substantially the same language. Of those who settled in Iran, the Persians were the most prominent,--a brave, hardy, and adventurous people, warlike in their habits, and moral in their conduct. They were a pastoral rather than a nomadic people, and gloried in their horses and cattle. They had great skill as archers and horsemen, and furnished the best cavalry among the ancients. They lived in fixed habitations, and their houses had windows and fireplaces; but they were doomed to a perpetual struggle with a severe and uncertain climate, and a soil which required ceaseless diligence. "The whole plateau of Iran," says Johnson, "was suggestive of the war of elements,--a country of great contrasts of fertility and desolation,--snowy ranges of mountains, salt deserts, and fields of beauty lying in close proximity."