Al-Nasir Muhammad Salah al-Din or al-Nasir li Din Allah Muhammad Salah al-Din ibn Ali al-Mahdi was an imam of Yemen who ruled during the period 1372-1391.
Background
He was a Zaydi imam and a descendant of the Prophet Muhammad. Al-Nasir Muhammad Salah al-Din was a son of Ali al-Mahdi ibn Muhammad, who was an imam of Yemen who ruled during the period 1349-1372. About the middle of the century, his father Ali al-Mahdi ibn Muhammad attained considerable influence, which was however reduced before his death in Dhamar in 1372.
Career
In the first half of 14th century, several imams had disputed the succession. Al-Nasir Muhammad Salah al-Din became the sole Zaydi imam of Yemen. In the year after his accession, al-Nasir Muhammad Salah al-Din attempted to seize San'a, but was unable to penetrate the strong defences.
Instead, he resorted to strategy. Idris and his mother were allowed to live in the city, but had no further contact with the imam. Al-Nasir Muhammad Salah al-Din was a comparatively successful ruler.
He advanced as far as the Tihama in the coastland of South Arabia, moving against the Rasulids. In 1391 he was thrown off his mule and dragged along, receiving fatal injuries. When he died in San'a, his death was concealed for two months on account of insecurity.
He is buried in the Salah al-Din Mosque, built on his initiative. He was the husband of as-Sayyidah Fatimah, daughter of the headman of the Kurds in Dhamar, who built the al-Abhar Mosque in San'a. Al-Nasir Muhammad Salah al-Din wrote a commentary on al-Zamakhshari's al-Kalim al-Nawabigh.
He titled his work al-Hikam al-Sawabigh fi al-Kalim al-Nawabigh. In the same period of time, al-Taftazani (d 1390) wrote also a commentary on al-Zamakhshari's work with slightly different title: al-Ni'am al-Sawabigh fi al-Kalim al-Nawabigh.