Around the first millennium bce Persian tribes migrated to the Iranian plateau, the landmass defined by the mountain range of the Zagros in the west, the Caucasus Mountains in the northwest, the Caspian Sea in the north, the Indus River in the east and the Indian Ocean and the Persian Gulf in the south and southwest. The Iranian plateau features a rich geographical diversity ranging from the mountainous regions of the Zagros range and the Alburz range, which reaches its highest peak with Mt. Damavand (5610m), to the lush and fertile regions south of the Caspian Sea, the Central Asian steppe with its grasslands and savannah, interrupted only by the two large rivers, the Oxus (mod. Amu Darya) and the Jaxartes (mod. Syr Darya), the desert regions of the Dash‐e Kavut and Dasht‐e Lut and the mountain and desert regions of the southeast. In the southwest, the plateau borders on the Mesopotamian lowlands, and in the northeast on the mountain ranges of the Hindukush and the Himalayas (Map 2.1). Agriculture allowed for the planting of wheat, emmer and barley, while pastures secured the breeding of small livestock, such as sheep, goats and fowl, as well as horses and camels.
The Persians were an Indo‐Iranian people who spoke an Iranian language which we now refer to as Old Persian. Theirs was an oral society which, prior to their settlement on the Iranian plateau, had had no need for written records. What triggered the undoubtedly hazardous and arduous migration of Persian tribes from the east is not known; we can only hypothesise that the reasons were economic, namely the need to find new land to feed families and livestock. It may have been due to political pressure in their original homeland or wars and military conflicts which had threatened or destroyed their way of life. The overland routes these tribes took before finally settling on the Iranian plateau remain an unresolved issue. What we do know, based on our extant sources, is that this migration movement and the processes of settlement happened peacefully, neither using military aggression towards the indigenous populations they encountered, nor forcing their displacement in turn for Persian settlement.
To achieve such a successful process of acculturation, the Persians must have met with the acceptance of the local population, while they, in turn, must have shown a significant willingness to adapt to their new cultural surroundings, to accept their hosts’ way of life while offering their own expertise to them.
The Achaemenid Empire the First Ever Persian Glory
