The more direct routes to India from Ecbatana, passing through Central Persia _via_ Kashan, Yezd, and Kirman, terminated on the Helmund or in Makran, and there is no evidence that the mountain system which faces the Indus was ever crossed by invading Persian hosts. There was, indeed, a tradition in Alexander's time that an attempt had been made to traverse Makran and that it had failed. This, says Arrian, was one of the reasons why Alexander obstinately chose that route on his retirement from India. In spite, however, of the geographical difficulties which render it improbable that the hosts of Tiglath Pileser (who could have dealt with the Skythians of the north readily enough) ever broke across the north-western gateways of India's mountain borderland, there was undoubtedly a close connection between Assyria and India of which the evidence is still with us.
Throughout the golden age of the Second Empire of Assyria, after the subjugation of Babylon and the consolidation of the Empire by Tiglath Pileser, during the reigns of Sargon and Senacherib (who fought the first Assyrian naval fight), Esar Haddon (who destroyed Sidon and removed the inhabitants) and Assur-bani-pal (Sardanapalus), to the final overthrow of Assyria by Babylon in 625 B.C., when the star of Nebuchadnezzar arose on the southern horizon, Assyria held the supreme command of Eastern commerce, and Nineveh dictated the cannons of art to the world. No event more profoundly affected the commerce of Asia than the destruction of Sidon and the bodily transfer of its commercial inhabitants to Assyria. This was the age of Assyrian art, of literature, and of architecture; Assyrian culture realized its culminating point in the reign of Assur-bani-pal, when the library at Nineveh far surpassed any library that the world had ever seen. It was then that intercourse between Assyria and India became unbroken and intimate. Then public works of the largest dimensions were undertaken, and colonies formed for the purpose of developing the riches of the newly acquired lands in the East. Assyrian art found its way to India, and the affinity between Assyrian and Indian art is directly traceable still in spite of the impress subsequently effected by Greece and Rome.