Al-Mustarshid had been succeeded by his son Al-Rashid.
Like his father, ar-Rashid makes another failed attempt at independence from the Seljuq Turks.
To avenge his father's death, he insults Sultan Mas'ud's envoy, who comes to demand a heavy largess, incites the mob to plunder his palace, and then, supported by Zengi, who is equally hostile to the Sultan because of the murder of Dubeis, sets up a rival Sultan.
Mas'ud hastens to the rebellious capital and lays siege to it.
Baghdad, well defended by the river and its canals, resists the attack; but in the end, the Caliph and Zengi, hopeless of success, escape to Mosul.
The Sultan's power restored, a council is held, the Caliph deposed, and his uncle, Al-Muqtafi, appointed as the new Caliph.
Ar-Rashid flees to Isfahan, where he will be killed by Hashshashins in 1138.