Al-Musta'sim

Abu Ahmad Abdallah ibn al-Mustansir bi'llah (Arabic: أبو أحمد عبد الله بن المستنصر بالله), better known by his regnal title Al-Mustaʿṣim bi-llāh (Arabic: المستعصم بالله;‎ 1213 – 20 February 1258), was the 37th and last caliph from the Abbasid dynasty ruling from Baghdad. He held the title from 1242 until his death in 1258.