The Caliphate of al-Mustansir Abū al-Qāsim Aḥmad ibn al-Ẓāhir ibn al-Nāṣir al-ʿAbbāsī in Egypt
This caliph was the brother of al-Mustansir, the founder of the Mustanṣiriyya (1), and the uncle of al-Mustaʿṣim. He was given the oath of allegiance as caliph in Egypt; al-Malik al-Ẓāhir, the chief judge, the vizier, and the emirs all swore fealty to him. He then mounted the caliphal throne in the land of Egypt, the emirs riding before him while the populace thronged about him, and he processed through Cairo—[a day long remembered]—on the thirteenth of Rajab (2).
He was the thirty-eighth caliph of the Abbasid house, with twenty-four forefathers between him and al-ʿAbbās. The first to pledge allegiance to him was Chief Judge Tāj al-Dīn, once his lineage had been verified (3); next came the sultan [al-Malik al-Ẓāhir], then Shaykh ʿIzz al-Dīn ibn ʿAbd al-Salām (4), after whom came the emirs (5) and the officials of state. His name was proclaimed from the pulpits and struck upon the coinage.
The caliphal office had remained vacant for three (6) years and a half, for al-Mustaʿṣim had been killed at the beginning of 656 AH, and this caliph received the bayʿa on Monday, the thirteenth of Rajab of the present year—that is, 659 AH. He was dark-complexioned, handsome, powerfully built, lofty in ambition, courageous and bold. They conferred on him the honorific “al-Mustansir” (7) just as his brother (8), the founder of the Baghdad madrasa, had been called; never before had two brother caliphs shared the same laqab.
[Moreover], the caliphate had previously passed to two brothers (9): al-Saffāḥ and his brother al-Manṣūr, the sons (10) of Muḥammad ibn ʿAlī ibn ʿAbd Allāh ibn al-ʿAbbās; al-Hādī and al-Rashīd, the sons of al-Mahdī ibn al-Manṣūr; al-Wāthiq and al-Mutawakkil, the sons of al-Muʿtaṣim ibn al-Rashīd; and al-Mustarshid and al-Muqtafī, the sons of al-Mustaẓhir. As for groups of three, they were al-Amīn, al-Maʾmūn, and al-Muʿtaṣim, the sons of al-Rashīd; al-Muntaṣir, al-Muʿtazz, and al-Muʿtamid, the sons of al-Mutawakkil; and al-Muttaqī, al-Rāḍī, and al-Muṭīʿ (11), the sons of al-Muqtadir. As for four, they were the sons of ʿAbd al-Malik ibn Marwān—