The Ayyubids failed to capture the Zaydis stronghold in northern Yemen. In 1191, Zaydis of Shibam Kawkaban rebelled and killed 700 Ayyubid soldiers. Imam Abdullah bin Hamza proclaimed the imamate in 1197 and fought al-Mu'izz Ismail, the Ayyubid Sultan of Yemen. Imam Abdullah was defeated at first but was able to conquer Sana'a and Dhamar in 1198, and al-Mu'izz Ismail was assassinated in 1202.