Ali bin al-Mu'ayyad was a fifth-generation descendant of the imam al-Hadi Yahya (d. 1239). After the demise of imam an-Nasir Muhammad Salah ad-Din in 1391, a struggle broke out between his son al-Mansur Ali and another contender, al-Mahdi Ahmad bin Yahya. Al-Mansur imprisoned his opponent in 1392, but was then challenged by Ali bin al-Mu'ayyad, who took the honorific (laqab) name al-Hadi Ali. During his almost 40 years long imamate he was generally overshadowed by al-Mansur Ali, who was celebrated as a mujaddid bi-sayfihi, a warlike restorer, and who died only in 1436. Nevertheless, al-Hadi Ali had a following and was counted by some as a mujaddidun. These are figures who, according to a hadith, will appear every century to restore Islam. He died in 1432, leaving ten sons, of whom al-Hasan (1401–1486) became a prominent scholar. Al-Hasan's son in turn, al-Hadi Izz ad-din, held the Zaidi imamate in 1474–1495.
- The line of descent is: al-Hadi Yahya – Ali – Muhammad – Jibril – al-Mu'ayyad – al-Hadi Ali; see Imam Zaid bin Ali Cultural Foundation, http://www.izbacf.org/page_display.php?book_id=37&page_num=51 .
- Ella Landau-Tasseron, 'Zaydi Imams as Restorers of Religion; Ihya and Tajdid in Zaydi Literature', Journal of Near Eastern Studies 49:3 1990, p. 260.
- Madeleine Schneider, 'Deux études d'épigraphie arabe', Journal asiatique 275 1987, p. 234.
al-Mahdi Ahmad bin Yahya
|Imam of Yemen
al-Mansur Ali bin Salah ad-Din