al-Muqtadir bi-Allāh

The accession of al-Muqtadir bi-Allah in 908 placed a boy of about thirteen on the Abbasid throne, the youngest caliph the dynasty had yet seen, and his long reign of twenty-four years became a byword for the decay of the caliphate's central power. He was Ja'far, a son of the vigorous restorer caliph al-Mu'tadid, and succeeded his brother al-Muktafi. Court factions chose him precisely because of his youth, and within months a group of officials attempted to replace him with the poet-prince Ibn al-Mu'tazz, a coup that collapsed within a day.

Real power throughout the reign lay with the court: with his mother Shaghab, whose household controlled great wealth and influence; with a rapid succession of viziers, among them the rivals Ibn al-Furat and Ali ibn Isa, repeatedly appointed, dismissed, fined, and reinstated; and increasingly with army commanders. Government became a cycle of confiscations and expedients as an extravagant palace establishment consumed revenues that the provinces supplied ever less reliably. The treasury reserves accumulated by his father and brother were spent.

The losses of the period were lasting. The Fatimid caliphate, established in North Africa in 909, openly denied Abbasid legitimacy and threatened Egypt. The Qarmatians of eastern Arabia ravaged Iraq's pilgrimage routes and in 930 sacked Mecca itself, carrying off the Black Stone from the Kaaba, an event that shocked the Islamic world. Provincial dynasties consolidated their independence while Baghdad's authority contracted toward Iraq. The reign also had brighter aspects, including the famous reception of Byzantine envoys at the caliphal palaces, recorded in detail by later writers, and it was under al-Muqtadir that the physician al-Razi and other scholars worked in Baghdad.

Al-Muqtadir was briefly deposed in 929 in favour of his brother al-Qahir but restored within days by loyal troops. The end came in 932, when he confronted his own general, the veteran commander Mu'nis al-Muzaffar, in battle outside Baghdad and was killed. After him, caliphs were made and unmade by soldiers, and within a few years the Buyids reduced the Abbasids to figureheads. His reign is conventionally treated as the point at which the decline of the caliphate became irreversible.