Sa'da

Sa'da (Sa'dah), in the northern highlands of Yemen, is the historic heartland of Yemeni Zaydi Shi'ism. The first Zaydi imam of Yemen, al-Hadi ila al-Haqq Yahya (d. 911), established his imamate there in 897, founding a Zaydi state and a tradition of religious-political leadership that endured intermittently into the 20th century.