[[Al-Mustaʿṣim bi-llāh|Abu Ahmad Abdallah ibn al-Mustansir bi'llah]], better known by his regnal title [[Al-Mustaʿṣim bi-llāh]] ([[1213-01-01 - 1258-02-20|1213 – 20 February 1258]]), was the 37th and last caliph from the [[Abbasid dynasty]] ruling from [[Baghdad]]. He held the title from [[1242-01-01 - 1258-02-20|1242 until his death in 1258]].