Uthman gave permission to Muawiyah to build a navy. From their base in Syria, the Muslims used this fleet to capture Cyprus in 649, Crete, and Rhodes. Annual raids into western Anatolia dissuaded the Byzantines from further attempts to recapture Syria. In 654–655, Uthman ordered the preparation of an expedition to capture Constantinople, but, due to unrest in the caliphate that resulted in his assassination in 655, the expedition was delayed for decades, only to be attempted unsuccessfully under the Ummayads.