In ancient times, Iran was known as Persia and inhabited by the Persians. The Persians were descended from ancient nomads called the Parsa. The most famous kings of Persia were Cyrus the Great, Darius the Great, and Xerxes. The Persians had an empire which had parts of Africa, the middle east, and Eastern Europe. This empire was called the Achaemenid Empire which lasted from 550 to 330 BC.
Like the ancient Greeks, the ancient Persians worshipped many gods. A Persian philosopher called Zoroaster founded a religion influenced by the ancient religion, but with only two gods. This religion was called Zoroastrianism. The two gods were Ahura Mazda, the creator, and Angra Mainyu, the evil god. Zoroastrianism influenced later religions like Judiasm, Christianity, and Islam.