In 924 he helped secure the dismissal and execution of his long-time rival, the vizier Ibn al-Furat, after which his political influence grew enormously, to the point that he briefly deposed al-Muqtadir in 928.
His rivalry with the caliph and with the civilian bureaucracy of the court finally resulted in an open confrontation in 931–932, that ended with Mu'nis's victory and al-Muqtadir's death in battle.
Mu'nis's usurpation of power, just as his violent end, marked the beginning of a new period of turmoil for the declining Abbasid Caliphate, culminating in its takeover by the Buyids in 946.
[2] Mu'nis rose to prominence early during the reign of al-Muqtadir: in December 908, shortly after the caliph's accession, a faction of the bureaucracy and the army launched a coup to depose him and replace him with his brother Abdallah ibn al-Mu'tazz.
This earned him the gratitude and support of the young caliph and his influential and powerful mother, Shaghab, and solidified his position among the grandees of the Abbasid court.
[5] In 914, the Fatimids, who had only a few years before taken over Ifriqiya by ousting the reigning Aghlabids, launched an invasion of Egypt under Abu'l-Qasim, the future caliph al-Qa'im bi-Amr Allah.
[6] In September/October 917, in response to a Byzantine embassy led by John Rhadenos, he supervised, along with Bishr al-Afshini, the governor of Tarsus and the Cilician thughur, another prisoner exchange on the Lamos River.
[6] In 918–919, Mu'nis campaigned against the rebellious ruler of Adharbayjan, the Sajid Yusuf ibn Abi'l-Saj,[3] who withheld part of the taxes owed to Baghdad and had even seized provinces in northern Iran from the Samanids without the Caliph's approval.
This was a troubled period, which saw Mu'nis sent to quasi-exile in Raqqa, the widespread torture of the Banu'l-Furat's political opponents, as well as the resurgence of the Qarmatian threat with the sack of Basra and the destruction of the Hajj caravan returning from Mecca.
[1][14][15] This marked the apogee of Mu'nis's career: he was now in virtual control of the government and a decisive voice in the appointment of Ibn al-Furat's successors as viziers.
[16] In 928, following the dismissal of his favourite, Ali ibn Isa, from the vizierate,[16] Mu'nis launched a coup and deposed al-Muqtadir and installed his half-brother al-Qahir in his place, but reneged after a few days.
Historian Michael Bonner writes of him that he "kept the remnants of the army together and saved the caliphate on several occasions",[18] while according to the Orientalist Harold Bowen, "Mu'nis's influence was on the whole exerted for good", but he was "neither strong nor intelligent enough" to prevent the renewed decline of the Abbasid state.
[1] On the other hand, his seizure of power by military force and the killing of a caliph—the first such incident since the Anarchy at Samarra two generations before—set a dangerous precedent and heralded a new period of anarchy; after his death, powerless caliphs became puppets in the hands of a series of regional military strongmen, who vied for the title of amir al-umara and control of the Abbasid government and its revenue until Baghdad, and the Abbasid Caliphate with it, fell to the Buyids in 946.