Theologian. Jamaluddin studied with Nasiruddin Tusi, a noted philosopher of his age and authored Al Bab al Hadi Ashar, Sharh Tajrid al Itiqat, the standard reference books for Asna Ashris (The twelvers). Jamaluddin immigrated to Iran in 1305 and converted Oljeytu the eighth Khan of Iran from the Sunni to Shia sect. In 1305 Shia was proclaimed the state religion of Iran. Jamaluddin was born at Hillah, Iraq, and was buried in Mashhed.