With the passage of time, in the middle of the second millennium BCE, the Indo-Iranian peoples, namely the Persians, entered the Iranian plateau and settled in the southern parts and on the eastern side of the Zagros Mountains, behind the eastern borders of Elam. After years of settlement and taking advantage of the political situation in the region, they gradually and apparently without severe military confrontations, entered the land of Anshan and founded the city of Pasargadae. Anshan, which formed the eastern territory of the Elamite kingdom and was bordered by the Persians from the north and east, witnessed the interaction of this migrant people with the ancient state of Elam from the very beginning.
The presence of the Persians in the vicinity of Elam and their subsequent dominance over the land of Anshan laid the groundwork for complex political and military relations between these two peoples. The frequent Assyrian invasions against Elam, which intensified during the eighth and early seventh centuries BCE, led to the establishment of friendly relations between the Persians and the Elamite state in the form of political-military alliances to counter the common threat of the Assyrians. This cooperation indicates the Elamites' use of the Persians' military capabilities against Assyria.
On the other hand, the presence of the Persians in the neighborhood of the Elamites and their later rule over the land of Anshan caused the Persians to be greatly influenced by the Elamite experiences of statecraft and culture. For example, Cyrus II used the traditional title of "King of Anshan," which was used by the Elamites. Also, in the reliefs of Persepolis, the similarity of Persian daggers to Elamite military equipment is evident, and even Cambyses, the son of Cyrus the Great, participated in the New Year festival in Babylon wearing Elamite attire. This shows the deep influence of Elamite culture and governance on the Persians.
The first reports of an alliance between the Persians and Elam date back to the time of Shutruk-Nahhunte II (717–699 BCE). After that, to counter Assyrian influence, these alliances between Elam, the Persians, and other regional powers expanded. As such, in 691 BCE, Sennacherib, the king of Assyria, claims to have defeated the Elamite army along with its allies, one of which was the Persians, in the Battle of Halule. This evidence shows that the Persians established friendly relations with the Elamites from the beginning and participated several times as an ally of the Elamite state in the war against the Assyrians.
Sources repeatedly speak of the cooperation of Cyrus I with the Elamites during the war between Shamash-shum-ukin, the ruler of Babylon, and his brother Ashurbanipal. Also, Assyrian sources report the retreat of the Elamite king Humban-nikash with men from the land of Parsuash and speak of the connection of the Persians with Elam during the time of Tammaritu, who summoned troops from the region of Hidalu and Parsuash for the war against Assyria. These documents emphasize the important role of the Persians in Elamite foreign policy against Assyria and the Elamites' use of Persian military power and experience against Assyria.
Although we are somewhat aware of the establishment of contact between the Persians and the Elamites through Assyrian sources, we do not have much information about the exact time of the Persians' entry into Anshan and its capture. The first reference to the presence of the Persians in Anshan can be inferred from the claim of Cyrus I and a seal impression found in Persepolis, in which Cyrus I uses the title "Cyrus the Anshanite, son of Teispes" for himself. After that, Cyrus II, Cyrus the Great, also claims in his famous cylinder that his ancestors were kings in Anshan for three generations before him, since the time of Teispes.
It seems that the Persian rule over Anshan was accomplished gradually and peacefully, and this shift of power in Anshan did not greatly disrupt the previous friendly relations. It even seems that the Persian rule over Anshan, much like Cyrus the Great's victory over Astyages, was interpreted as a transfer of power rather than a violent conquest. Perhaps this is why, until the time of Cyrus the Great, the Persian rulers of Anshan used the title "King of Anshan" for themselves instead of "King of Persia," and these friendly relations with Elam continued.