Complex sentence: The tomb and shrine of Aqil ibn Abi Talib (the brother of Ali) was located in al-Bāb, and until its rule by the Ayyubids in the 13th century, the town was populated mostly by Shias of the Ismaili sect.
Split into simpler sentences: The tomb and shrine of Aqil ibn Abi Talib (the brother of Ali) was located in al-Bāb. Until its rule by the Ayyubids in the 13th century, the town was populated mostly by Shias of the Ismaili sect.