Abu'l-Abbas Ahmad (Muhammad) ibn Ja'far al-Muqtadir (Arabic: ??? ?????? ???? (????) ?? ???? ????????, romanized: Abu al-?Abbas A?mad (Mu?ammad) ibn al-Muqtadir; December 909 – 23 December 940), usually simply known by his regnal name ar-Radi bi'llah (Arabic: ?????? ??????, romanized: ar-Ra?i bi'llah, lit.
'Content with God'), was the 20th Caliph of the Abbasid Caliphate, reigning from 934 to his death.
He died on 23 December 940 at the age of 31.
His reign marked the end of the caliph's political power and the rise of military strongmen, who competed for the title of amir al-umara.