Abd al-Malik, the Umayyad caliph, defeated Mus'ab ibn al-Zubayr, the brother of the rival caliph Abd Allah ibn al-Zubayr, in the Battle of Maskin in 691. This victory gave Abd al-Malik control of Iraq and further solidified his claim to the caliphate.
Conquest and Caliphate: The Tale of Abd Allah ibn al-Zubayr