Zoroastrianism is a religion that was founded by Zoroaster around the 2nd millennium BC. It is widely considered the first monotheistic religion. Founded in Persia, it was spread by the Achaemenid Empire. Today, it has been largely supplanted by Islam and Christianity, with about 200,000 followers located mostly in Iran. Zoroastrianism features a belief in an almighty god that is the source of all good and no evil, similar to the ideas of the Abrahamic religions of Judaism, Christianity and Islam.