 Complete the following phrase:  Following a failed invasion of Iraq in 686, Abd al-Malik focused on securing Syria before making further attempts to conquer the greater part of the Caliphate from his principal rival, the Mecca-based caliph Abd Allah ibn al-Zubayr. To that end, he concluded an unfavorable truce with the reinvigorated Byzantine Empire in 689, quashed a coup attempt in Damascus by his kinsman, al-Ashdaq, the following year, and reincorporated into the army the rebellious Qaysi tribes of the Jazira Upper Mesopotamia in 691. He then conquered Zubayrid Iraq and dispatched his general, al-Hajjaj ibn Yusuf, to Mecca where he killed Ibn al-Zubayr in late 692, thereby reuniting the Caliphate under Abd al-Maliks rule. The 