| Mansûr al-Mustansir bi-llah المنصور المستنصر بالله | |
| Khalīfah Amir al-Mu'minin | |
| Succession: | 36th Caliph of the Abbasid Caliphate Abbasid Caliph in Baghdad |
| Reign: | 10 July 1226 – 5 December 1242 |
| Predecessor: | al-Zahir |
| Successor: | al-Musta'sim |
| Birth Date: | 17 February 1192 [1] |
| Birth Place: | Baghdad, Abbasid Caliphate, (now Iraq) |
| Death Date: | 5 December 1242 (aged 50) |
| Death Place: | Baghdad, Abbasid Caliphate |
| Burial Place: | Baghdad |
| Spouse-Type: | Consort |
| Spouse: | Shahan Hajir[2] |
| Full Name: | Abu Ja`far Mansûr al-Mustansir bi-llah ibn az-Zâhir |
| Dynasty: | Abbasid |
| Father: | al-Zahir |
| Mother: | Zahra |
| Issue: | Al-Musta'sim |
| Religion: | Sunni Islam |
Al-Mustansir Bi'llah (full name:Abû Ja`far al-Mustansir bi-llah al-Mansûr bin az-Zâhir[3] surname al-Mustansir),[4] (17 February 1192 – 2 December 1242) was the Caliph of the Abbasid dynasty from 1226 to 1242. He succeeded Caliph Az-Zahir in the year 1226 and was the penultimate caliph to rule from Baghdad.
Al-Mustansir was born in Baghdad on 1192. He was the son of Abu Nasr Muhammad (future caliph Al-Zahir). His mother was a Turkish Umm walad.[5] [6] called Zahra. His full name was Mansur ibn Muhammad al-Zahir and his Kunya was Abu Jaʿfar. At the time of his birth, his father was a prince. When his father ascended to the throne in 1225. His father, lowered the taxes of Iraq, and built a strong army to resist invasions. He died on 10 July 1226, nine months after his accession.
On his father's death in 1226 he has succeeded his father Az-Zahir as the thirty-sixth Abbasid caliph in Baghdad. Al-Mustansir is particularly known for establishing Mustansiriya Madrasah (currently a part of the Al-Mustansiriya University) in 1227/32/34. The Madrasah, at the time, taught many subjects including medicine, mathematics, literature, grammar and Islamic religious studies, becoming a prominent and high-ranking center for Islamic studies in Baghdad.[7] The Madrasas during the Abbasid period were used as the predominant instrument to foster the spread of Islamic thought as well as a way to extend the founder's pious ideals.[8]
The ruler of Erbil, Muzaffar ad-Din Gökböri was being without a male heir, Gökböri willed Erbil to the Abbasid caliph al-Mustansir.[9] After the death of Gökböri in 1233, the Erbil city came under Abbasid control.
Al-Mustansir died on 5 December 1242.[10] His son Al-Musta'sim succeeded him as the thirty-seventh and last Caliph of the Abbasid Caliphate.
One of Al-Mustansir's concubines was Shahan. She was a Greek, and had been formerly a slave of Khata Khatun, the daughter of the commander Sunqur al-Nasiri the Tall and the wife of the commander Jamal al-Din Baklak al-Nasiri. After Al-Mustansir's accession to the throne, Khata presented Shahan to him as a gift, as part of a group of slaves. Shahan alone among them became his concubine and favourite.[11] Another of his concubines was Hajir. She was the mother of the future Caliph Al-Musta'sim.[12]