After losing the Levant, the economic lifeline of Byzantines and Armenia, the manpower hub, Emperor Heraclius was left incapable of any military come back, he rather focused to consolidate his power in Egypt. In his visit to Syria in 637 to receive surrender of Jerusalem, Amr ibn al-Aas tried to convince Umar for the invasion of Egypt, but Umar rejected on the ground that Muslim rule in Syria was still not firm. After the great plague in 639, Umar paid a visit to Syria and was again persuaded by Amr for the invasion of Egypt.