Al-Mansur or Abu Ja'far Abdallah ibn Muhammad al-Mansur (95 AH – 158 AH (714 AD – 775 AD); Arabic: أبو جعفر عبدالله بن محمد المنصور) was the second Abbasid Caliph from 136 AH to 158 AH (754 AD – 775 AD). He is generally regarded as the real founder of the Abbasid Caliphate.