Ibn al-Murtaḍá, Aḥmad ibn Yaḥyá, 1363-1437

Al-Mahdī Aḥmad ibn Yaḥyā, or Aḥmad ibn Yaḥyā Ibn al-Murtaḍā (أحمد بن يحيى المرتضى) (1363/1374 – 1436), was a Muʿtazila scholar and imam of the Zaidī state in Yemen who briefly held the imamate in 1391–1392. He was an encyclopedist and a prolific writer on a range of subjects. Aḥmad ibn Yaḥyā was a 12th-generation descendant of the Zaidī imām ad-Da'i Yusuf (d. 1012). His full name was: al-Mahdī Aḥmad ibn Yaḥyā ibn al-Murtaḍā ibn Aḥmad al-Jawad ibn al-Murtaḍā ibn al-Mufaḍḍal ibn al-Manṣūr ibn al-Mufaḍḍal ibn al-Ḥajjāj ibn Alī ibn Yaḥyā ibn al-Qāsim ibn al-Da'ī Yūsuf. In 1391, when the elderly imām al-Nasir Muhammad Salah al-Din died, his sons were still minors. The qāḍī, ad-Dawwarī, took temporary administration of the Zaidī domains of highland Yemen, in their name. However, the Zaidi ulema assembled in the Jamal ad-Dīn Mosque in San'a and appointed Aḥmad ibn Yaḥyā imām under the title 'al-Mahdī Aḥmad'. The appointment was not recognised by ad-Dawwani, who immediately appointed the deceased imām's son al-Mansur Ali bin Salah ad-Din. Al-Mahdī Aḥmad and his followers withdrew from San'a to Bayt Baws, and for one year the two imāms fought for supremacy. In 1392, al-Mahdī Aḥmad was captured by al-Manṣūr Alī's forces and imprisoned. In 1399, aided by prison guards, the ex-imām escaped to live in privacy until his death from plague in 1436. Although al-Mahdī 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.