Answer
Mu'awiya was the first Umayyad caliph. In order to keep the large Umayyad caliphate under control, Mu'awiya delegated authority to two of his most trusted generals, Al-Mughira and Ziyad ibn Abi Sufyan. Al-Mughira was in charge of Iraq and the eastern provinces, while Ziyad was in charge of the western provinces.