Al-Musta'in

Al-Musta'in bi-llah المستعين بالله
Gold dinar of al-Musta'in
12th Caliph of the Abbasid Caliphate
Reign	8 June 862 — 17 October 866
Predecessor	al-Muntasir
Successor	al-Mu'tazz
Born	836
Died	17 October 866
Dynasty	Abbasid
Father	Muhammad
Religion	Islam

Al-Mustaʿin (836 – 17 October 866) was the Abbasid Caliph from 862 to 866, during the "Anarchy at Samarra". After the death of previous Caliph, al-Muntasir (who had not appointed any successors), the Turkish military leaders held a council to select his successor. They were not willing to have al-Mu'tazz or his brothers; so they elected Ahmad ibn Muhammad أحمد بن محمد, a grandson of al-Mu'tasim, who took the regnal name al-Mustaʿin bi-llah (المستعين بالله "he who looks for help to God").

Arab and other troops based in Baghdad, displeased at the choice, attacked the assembly, broke open the prison, and plundered the armory. They were attacked by the Turkish and Berber soldiers, and after some fighting in which many died, succumbed. Baghdad had yet to learn that the Caliphate no longer depended on the opinions of the Arabians, but had passed into other hands.

The governor of Baghdad persuaded the city to submit, and the succession was thereafter acknowledged throughout the land. Al-Mu'tazz and his brother, threatened by the Turkish and Berber troops, resigned their titles to succeed, and were then, by way of protection, kept in confinement. After a second attempt to overturn the decision made by the Turks, Al-Mu'tazz and his brother would have been put to death, but the vizier interposed and saved their lives, for which act of mercy, his property was seized by the Turkish soldiers, and himself banished to Crete. The Empire, in fact, both at home and abroad, had passed into the hands of Turks.

In 863, the Muslim campaign against the Christians was going badly. Two whole corps in Armenia and Asia Minor, some 8,000 strong, with their leaders, were killed during the Battle of Lalakaon. The tidings created anger and riots in Baghdad. The ancient cry for a Holy War rang through the streets. People blamed the Turks that had brought disaster on the faith, murdered their Caliphs, and set up others at their pleasure.