The kingdom of Elam had already been part in the sort of power politics of the ancient Near East before Cyrus and indeed had been invaded by Ashurbanipal.
Elam itself has an ancient tradition of writing and the city of Susa in the lowland part of that kingdom is a very ancient city from the third millennium onwards.
A dire vision has been shown to me: The traitor betrays, the looter takes loot. Elam, attack! Media, lay siege! I will bring to an end all the groaning she caused.
After creating the first standing army known in history, he took his trained fighters and crossed the Tigris River and the rugged terrain of the eastern mountains into Elam, a place no Sumerian army had ever gone.
I will shatter Elam before their foes, before those who want to kill them; I will bring disaster on them, even my fierce anger, " declares the Lord. " I will pursue them with the sword until I have made an end of them.