Ancient Greek propaganda painted the Persian Empire as an enslaver of people, which was totally untrue. The truth is the people of the Persian Empire were more free than the Greeks at that time. Slavery had been abolished in the Persian Empire and still existed for over a 1,000 years after that in Greece.
The Persian Empire under Cyrus was the first Empire in History to proclaim that everyone had human rights. In the Persian Empire everyone had the right to worship any god they wanted to, the right to any occupation regardless of social status including high government positions, to live anywhere in the empire you wanted to and limited free speech rights, you could not call the King an S.O.B. to his face..
Parts of the US "Declaration of Independence" are taken directly from the Persian Empire's declaration of human rights.
When the Persians conquered Babylon they set the Jews free from Babylonian captivity and sent them home to Jerusalem. The Persians returned to the Jews what was left of what the Babylonians had stolen from Solomon's Temple and gave them money so they could rebuild Solomon's Temple, which was destroyed by the Babylonians.
The Persians, a few other Iranian tribes like the Massagetae and the Jews were the only people at that time in History who believed there was only one God.
Cyrus the Great was killed in a battle against the Massagetae, who were led into the battle by their Amazon Warrior Queen Tomyris. The battle took place in what is today Kazakhstan.