Baer, Eva (1983). Metalwork in Medieval Islamic Art. SUNY Press. s. xxiii. ISBN9780791495575. «In the course of the later eleventh and twelfth century, however, the Fatimid caliphate declined rapidly, and in 1171 the country was invaded by Ṣalāḥ ad-Dīn, the founder of the Ayyubid dynasty. He restored Egypt as a political power, reincorporated it in the Abbasid caliphate and established Ayyubid suzerainty not only over Egypt and Syria but, as mentioned before, temporarily over northern Mesopotamia as well.»
