Under Constans, the Byzantines completely withdrew from Egypt in 642, and Caliph Uthman launched numerous attacks on the islands of the Mediterranean and Aegean Seas. A Byzantine fleet under the admiral Manuel occupied Alexandria again in 645, and the Alexandrians hailed him as a liberator, since the caliphate levied heavier taxes and showed less respect for their religion. However, Manuel squandered his time and popularity in plundering the countryside, and eventually the Arab army managed to force him to embark for home. The situation was complicated by the violent opposition to Monothelitism by the clergy in the west and the related rebellion of the Exarch of Carthage, Gregory the Patrician. The latter fell in battle against the army of Caliph Uthman, and the region remained a vassal state under the Caliphate until civil war broke out and imperial rule was again restored.