The Biography of the Sultans of Kilwa

66 each other at the grave of the Prophet Muhammad, peace be upon him, that they should head for Yemen, and whoever of them took over, the other would serve as his visir, till the end. And so, they did. Arriving at Yemen, they found that King al-Mu’ayyad, the Ghassānid, had died and was succeeded by his son Mas'ūd who was in Aden at the time. The conditions of Yemen were in a terrible shape and the kingdom was on the verge of disintegration with almost all areas in disagreement with the current king Mas'ūd. However, since the two Alis were already in Yemen, the people gathered and gave their bai'ah (pledge of allegiance) to Ali ibn Tāher as their Caliph, thus disposing King Mas'ūd ibn al-Mu'ayyd, the Ghassānid.