After an-Nasirs sudden demise in 1391, no less than four claimants to the imamate appeared, foremost among them the learned al-Mahdi Ahmad bin Yahya.
However, a rival imam called al-Hadi Ali had some support in the northern parts of the Zaidi territory from 1393 to 1432.
Various strongholds of the Tayyibi Isma'ili sect were taken, and their leader Ali Shams al-Din II was forced out of Dhu Marmar, a fortress to the east of San'a.
Al-Mansur Ali's rule over San'a was never in danger, but in 1395 he sacked the qadi in the city, who had been found to correspond with the Rasulid Dynasty in the lowland.
[4] Towards the end his reign, especially after 1424, Rasulid power began to crumble when a number of short-lived sultans succeeded each other on the throne.