According to the book Hagarism, the Arab conquests and the formation of the caliphate were a peninsular Arab movement inspired by Jewish messianism. In alliance with the Jews, the Arabs attempted to reclaim the Promised Land from the Byzantine Empire. The Qur'an was a product of 8th-century edits of various materials drawn from a variety of Judeo-Christian and Middle-Eastern sources while Muhammad was the herald of Umar "the redeemer", a Judaic messiah.[4]