In 204 AH al-Maʾmun arrived, and the Abbasids together with the descendants of Abu Talib went out to meet him at Nahrawan. They reproached him for wearing green, so he hesitated and then returned to the black standard (1).

That same year Yahya ibn Muʿadh, the governor of al-Jazira, engaged Babak al-Khurrami (2). During the year as well, Tahir was given command over the whole of Khurasan, and an allowance of ten million dirhams was ordered for him.

In that year—namely, 205 AH—the Muslims were granted victory over Babak and caught him unawares in a night attack.

In 207 AH an Alid rebelled in Yemen (3); al-Maʾmun granted him amnesty, and he came to the caliph’s court.

Tahir died. It is said that before his death he had dropped al-Maʾmun’s name from the Friday sermon and revolted. After him his son Talha took charge; al-Maʾmun invested him with Khurasan, where he ruled for seven years and then died, after which his brother ʿAbd Allah ibn Tahir assumed the governorship (4).

The fighting between the Muslim army and Babak remained intense.

In Yemen a man known as al-Ṣanādiqī appeared; he killed people, carried off captives, claimed prophethood, and then died of the plague.

Hasan, brother of Tahir ibn al-Husayn, rebelled in Kerman; al-Maʾmun captured him and pardoned him.

Al-Maʾmun held the practitioners of speculative theology in high esteem and allowed them to debate in his presence. Ṣadaqa ibn ʿAli set out to fight Babak, but Babak captured him and grew even more defiant and headstrong.