Al-Mahdi Ali
Al-Mahdi Ali bin Mohammed (September 25, 1305 - 1372) was an imam of the Zaidi state in Yemen who ruled in 1349–1372. Acquiring the Zaidi imamate. The Yemeni imamate in the highlands was often contested by rival claimants in this era. Ali bin Muhammad al-Hosni was born in the village al-Ahani in the Sa'dah area in northern Yemen. He was not closely related to the recent imams, but an 11th-generation descendant of the imam ad-Da'i Yusuf. As a young man, Ali received a good deal of instruction in the religious sciences. In 1346 , the learned and powerful Imam al-Mu'ayyad Yahya died, and no politically strong figure emerged in his stead. Under these circumstances, Ali rose to power from his base in the mountain fortress Thula in 1349. In the presence of a numerous congregation of Zaidi scholars, he adopted the title al-Mahdi Ali and took possession of Sa'dah and Dhamar. At this time, San'a was dominated by two Zaidi emirs and brothers called Ibrahim bin Abdallah and Da'ud bin Abdallah. Al-Mahdi Ali laid siege to the city. However, the brothers held firm and after six months he had to lift  the siege and return to Thula. Support for Nur ad-Din. During his 23 years long reign, al-Mahdi Ali was nevertheless able to amass considerable political influence in Yemen. The powerful Rasulid Dynasty ruled the lowlands, but its grip on the northern inland had been shattered since some time. The Rasulid emir of Hadar, Nur ad-Din Muhammad bin Mika'il, turned rebellious against Sultan al-Mujahid Ali in 1359. In the next year, he sought support from the Zaidi elite of Sa'dah. Nur ad-Din entertained plans to take over the sultanate. Over the following years, he organized several  raids into Rasulid territory with Zaidi assistance, with mixed success. Al-Mahdi Ali bestowed the fortress Miftah as an appanage, and the rebel resided there until his demise in 1377. Al-Mahdi Ali himself died in Dhamar in 1372, after his authority had begun to recede. His body was carried to Sa'dah to be buried there. He was succeeded by his son an-Nasir Muhammad Salah ad-Din.