Complex sentence: Admiration of the Persians was especially high during the Achaemenid dynasty; its founder, Cyrus the Great, was the only Gentile to be considered a messiah in the Bible.
Split into simpler sentences: Admiration of the Persians was especially high during the Achaemenid dynasty. Its founder, Cyrus the Great, was the only Gentile to be considered a messiah in the Bible.