Al-Mahdë Aḥmad ibn YaḥyÃÂ, or Aḥmad ibn YaḥyàIbn al-Murtaá¸Âà() (1363/1374 â 1436), was a Muÿtazila scholar and imam of the Zaidë state in Yemen who briefly held the imamate in 1391âÂÂ1392. He was an encyclopedist and a prolific writer on a range of subjects.
Aḥmad ibn Yaḥyàwas a 12th-generation descendant of the Zaidë imÃÂm ad-Da'i Yusuf (d. 1012). His full name was: al-Mahdë Aḥmad ibn Yaḥyàibn al-Murtaá¸Âàibn Aḥmad al-Jawad ibn al-Murtaá¸Âàibn al-Mufaá¸Âá¸Âal ibn al-Maná¹£à «r ibn al-Mufaá¸Âá¸Âal ibn al-ḤajjÃÂj ibn Alë ibn Yaḥyàibn al-QÃÂsim ibn al-Da'ë Yà «suf.
In 1391, when the elderly imÃÂm al-Nasir Muhammad Salah al-Din died, his sons were still minors. The qÃÂá¸Âë, ad-Dawwarë, took temporary administration of the Zaidë domains of highland Yemen, in their name. However, the Zaidi ulema assembled in the Jamal ad-Dën Mosque in Sanaa and appointed Aḥmad ibn YaḥyàimÃÂm under the title 'al-Mahdë Aḥmad'. The appointment was not recognised by ad-Dawwani, who immediately appointed the deceased imÃÂm's son al-Mansur Ali bin Salah ad-Din. Al-Mahdë Aḥmad and his followers withdrew from Sanaa to Bayt Baws, and for one year the two imÃÂms fought for supremacy. In 1392, al-Mahdë Aḥmad was captured by al-Maná¹£à «r Alë's forces and imprisoned. In 1399, aided by prison guards, the ex-imÃÂm escaped to live in privacy until his death from plague in 1436. Although al-Mahdë Aḥmad lacked the requisite administrative and military skills for the Zaydiyyah imamate, he produced a substantial body of writings on dogmatics, logic, poetry, grammar and law.
His sister Dahma bint Yahya was also a scholar and poet. The famous Salafi scholar Muhammad Al-Shawkani wrote Al-Sayl al-jarrar, a denunciation of a text written by the Zaydi Imam Al-Mahdi Ahmad bin Yahya.