The History of the Jews in the Middle East

Iranian Jews are considered to be of the most ancient of the Jews. They stayed there for many decades or hundreds of years until finally King was at Cyrus allowed them to come back. There is one theory that a small group of Jews in 587 BC emigrated to Hejaz. Do they go back that ancient? I doubt this because that is taking the presence of the Yehud back a thousand years before the Prophet Sussadam. And that seems too early. But this is one theory.