Muʿtaṣim Billah, Abū Isḥāq b. Hārūn al-Rashīd.
On Thursday, the 12th of Rajab in the year 218 AH, in Tarsus, on the day his brother Maʾmūn passed away, allegiance (bayʿa) was given to him for the caliphate. When Maʾmūn fell ill and died in Tarsus, Muʿtaṣim Billah led his funeral prayer. Some of the commanders attempted to have Maʾmūn's son ʿAbbās chosen as caliph. However, ʿAbbās opposed them, saying: "What a cold opposition this is! I have pledged allegiance to my uncle Muʿtaṣim." Thereupon, the people calmed down and the flames of discord were extinguished. The postal service delivered the news of Muʿtaṣim's accession and the announcement of Maʾmūn's condolences throughout the country.
Muʿtaṣim ordered the demolition of the buildings Maʾmūn had constructed in the city of Ṭuwāna and that the weapons he had transported there be returned to the fortresses of the Muslims. He permitted the workers to return to their own towns. Afterwards, he took Maʾmūn's son ʿAbbās with him and set out with his army for Baghdad. At the beginning of Ramadan, on a Saturday, he entered Baghdad with great pomp and splendor.
In this year, a large group from among the people of Hamadan, Isfahan, Māsebezān, and Manrajān entered the Khurramite religion. Great crowds gathered around them. Muʿtaṣim dispatched many military units against them, the last of which was a large force under the command of Isḥāq b. Ibrāhīm b. Musʿab.
Thereupon, Muʿtaṣim appointed Isḥāq b. Ibrāhīm as governor of the Jabal region. He set out in the month of Dhu al-Qaʿda of that year. When he reached his assigned post, the conquest was achieved. Isḥāq b. Ibrāhīm sent a letter to Muʿtaṣim, informing him that on the day of Tarwiya (the eighth day of Dhu al-Ḥijja), the conquest had been accomplished, the Khurramites had been defeated, many of their men were killed, and the remainder had fled to Byzantium.
Through Ibrāhīm b. Isḥāq, Imām Aḥmad b. Ḥanbal was subjected to torture; that great figure was beaten in his presence and exposed to various forms of torment. As will be explained in detail when discussing the events of the year 241 AH, the biography of Imām Aḥmad b. Ḥanbal will be recounted there.