Answer
The answer is Al-Hajjaj ibn Yusuf, the Umayyad governor of Iraq who was tasked with suppressing the rebellion of Ibn al-Zubayr, who had proclaimed himself caliph in Mecca. Al-Hajjaj led a massive army to besiege Mecca, and after a protracted conflict, he eventually succeeded in defeating Ibn al-Zubayr and re-establishing Umayyad control over the Hejaz.