Qadi Iyad ibn Musa (1083–1149) (Arabic: القاضي عياض بن موسى, in French transliteration Qadi Iyad) or Abu al-Fadl `Iyad ibn Amr ibn Musa ibn `Iyad ibn Muhammad ibn Abdillah ibn Musa ibn `Iyad al-Yahsubi al-Sabti (أبو الفضل عياض بن موسى بن عياض بن عمرو بن موسى بن عياض بن محمد بن عبد الله بن موسى بن عياض اليحصبي السبتي ) born in Ceuta, then belonging to the Almoravid Empire, was the great imam of that city and, later, a high judge (qadi) in Granada.
He headed a revolt against the coming of the Almohades to Ceuta, but lost and was banished to Tadla and later Marrakech. He was a pupil of Abu Abdillah ibn Isa, Abu Abdillah ibn Hamdin and Abu al-Hassan ibn Siraj, and was a teacher of Averroes and Ibn Maḍāʾ.
He died in 1149. Because he refused to acknowledge Ibn Tumart as the awaited Mahdi, Qadi Ayyad was executed with a spear and his body subsequently cut to pieces. Although he was opposed to the Almohads and the ideas of Ibn Hazm, he did not hold enmity for the Zahirite school of Sunni Islam, which the Almohads and Ibn Hazm followed. Ayyad's comments on Ibn Hazm's teacher Abu al-Khiyar al-Zahiri were positive, as was Ayyad's characterization of his own father, a Zahirite theologian.
Cadi Ayyad University, also known as the University of Marrakech, was named after him. Qadi Ayyad is also well-known as one of the seven saints of Marrakech and is buried near Bab Aïlen.
He was one of the most famous scholars of Maliki law and author of the well-known Ash-Shifa on the virtues of the prophet and Tartib al-mardarik wa-taqrib al-masalik li-marifat alam madhab Malik, a collection of biographies of eminent Malikis, a.o. Abu Bakr ibn al-Arabi. Qadi `Iyad's other well known works include:
Ikmal al-mu`lim bi fawa'id Muslim, a famous commentary on Sahih Muslim which transmitted and expanded upon al-Maziri's own commentary, al-Mu`lim bi-fawa'id Muslim. Qadi `Iyad's own commentary was utilised and expounded upon heavily by Al-Nawawi in his own commentary of Sahih Muslim.
Bughya al-ra'i lima Tadmanahu Hadith Umm Zara` min al-Fawa'id, published with Tafsir nafs al-Hadith by Al-Suyuti.
al-I`lam bi Hudud Qawa'id al-Islam, written on the five pillars of Islam.
al-Ilma` ila Ma`rifa Usul al-Riwaya wa Taqyid al-Sama`, a detailed work on the science of Hadith.
^Delfina Serrano, "Claim or complaint?" Taken from Ibn Hazm of Cordoba: The Life and Works of a Controversial Thinker, pg. 200. Eds. Camilla Adang, Maribel Fierro and Sabine Schmidtke. Volume 103 of Handbook of Oriental Studies. Section 1 The Near and Middle East. Leiden: Brill Publishers, 2012. ISBN 9789004234246
"Qadi Iyad's Rebellion against the Almohads in Sabtah (A. H. 542-543/A. D. 1147-1148) New Numismatic Evidence", by Hanna E. Kassis, Journal of the American Oriental Society, Vol. 103, No. 3 (Jul.–Sep., 1983), pp. 504–514