From the outset of his unification of the Persians and Medes into a single imperial state, Cyrus the Great appears to have pursued two fundamental geopolitical objectives. In the east, he sought to contain any spillover from the movement westward of numerous hordes of Central Asian peoples that might threaten the integrity of the empire. To achieve this, it was necessary to extend the northeastern frontier of Persia to the Syr Darya (Jaxartes) River. Cyrus’ basic aim in that region was therefore primarily defensive in that he wanted to assure the security of his frontiers against encroachment. However, expansion eastward was not his highest immediate priority. The acknowledgment of his suzerainty by Hyrcania and Parthia in the region east of the Caspian Sea (Transcaspia) provided a degree of security on his eastern flank that permitted him to focus his initial efforts at imperial expansion in the west.
There his goal was conditioned by the prevailing geopolitical environment, which was far more complex than that which prevailed in the east. The situation that Cyrus found on his assumption of power was complicated and somewhat chaotic. For the preceding three centuries the Assyrians had managed, at considerable cost in blood and treasure, to keep open the mountain passes leading into Media, Armenia, and Cappadocia. After the fall of Nineveh (in 612 B.C.E.), the Medes had taken control of the eastern and northern passes, while those providing access to Anatolia to the northwest were under the effective control of the Lydians and Cilicians. Maritime traffic to and from the Phoenician ports was subject to depredations by pirates from the Lydian coast as well as by Greeks aligned with Egypt. At the same time, the Babylonians were doing what they could to maintain control of trade in the Persian Gulf region, and were aspiring to seize con-