The office of amir al-umara, variously rendered in English as emir of emirs, prince of princes, chief emir, and commander of commanders, was a senior military position in the 10th-century Abbasid Cali

Abu'l-Abbas Muhammad ibn Ja'far al-Muqtadir, usually simply known by his regnal name al-Radi bi'llah, was the twentieth Caliph of the Abbasid Caliphate, reigning from 934 to his death. He died on 23 D