Al-Mahdi Ahmad bin Yahya

Al-Mahdi Ahmad bin Yahya (1363? – 1436) was an imam of the Zaidi state in Yemen who briefly held the imamate in 1391–1392.
Ahmad bin Yahya was a 12th-generation descendant of the Zaidi imam ad-Da'i Yusuf (d. 1012), and was born in either 1363 or 1373. He was very well educated and a prolific writer in various subjects. In 1391, the old imam al-Nasir Muhammad Salah al-Din died, leaving only young offsprings. The qadi ad-Dawwari temporarily took care of the administration in the Zaidi domains of highland Yemen, in the name of an-Nasir's sons. However, the Zaidi ulema assembled in the Jamal ad-Din Mosque in San'a and appointed Ahmad bin Yahya imam under the name al-Mahdi Ahmad. This step was not accepted by ad-Dawwani, who immediately appointed the deceased imam's son al-Mansur Ali bin Salah ad-Din. Al-Mahdi Ahmad and his followers withdrew from San'a to Bayt Baws, and for one year the two imams fought each other for supremacy. In 1392, al-Mahdi Ahmad was captured by al-Mansur Ali's forces and imprisoned. In 1399 the ex-imam escaped with the help of sympathetic prison guards. He lived a private life until his death from the plague in 1436. While he lacked the administrative or military skills necessary for a Zaydiyyah imam, al-Mahdi Ahmad left a considerable amount of writings in dogmatics, logic, poetry, grammar and law. For example, he authored a theological-legal encyclopedia, Al-Bahr al-zahhar.