I say: He received the oath of allegiance at his father’s death, in Rabīʿ al-Ākhir of the year 512 AH. His rule therefore lasted seventeen years and seven months, and he lived forty-six years. It was said that the men who struck him had been outfitted by Masʿūd; they were seventeen in all. They were seized, the sultan put them to death, and he outwardly displayed grief and dismay.

Another report states that Sultan Sanjar ibn Malikshah sent word to his nephew Masʿūd, rebuking him for violating al-Mustarshid’s sanctity, ordering him to restore the caliph to his seat of honor, to walk before him beneath the ceremonial canopy, and to humble himself. Masʿūd complied in appearance only, while secretly working to have him killed. Others contended, rather, that it was Sultan Sanjar in Khurasan who had dispatched the Ismaʿili assassins against him, but that claim is remote.

It is also said that al-Shāshī composed his legal manual al-ʿUmda for al-Mustarshid.

In 517 AH there was a pitched battle between al-Mustarshid and Dubays al-Asadī; that day the caliph drew his sword, Dubays fled, and his forces were scattered (1). They met again in 519 AH, and Dubays was humbled; he came forward, kissed the ground, and was denied safe-conduct. He thereupon fled to Sultan Sanjar and sought his protection; Sanjar confined him in service to al-Mustarshid. On the Day of Sacrifice al-Mustarshid led the people in prayer, delivered the sermon, then descended and slaughtered a sacrificial camel with his own hand (2).

In 521 AH Sultan Maḥmūd arrived, besieged Baghdad, and the caliph gained the upper hand (3).

In 527 AH al-Mustarshid marched out with twelve thousand troops (4).