In the time of Uthman, the military organization set up under Umar was duly maintained. The Governor of each province acted as the com. mender of the forces. The Caliph acted as the Commander-in-Chief, and he directed the military activity under Umar, and extensive conquests
were made during the period. During the time of Uthman, most of Persia, Azarbauan, and Armenia revolted and these areas had to be reconquerd. Further conquests were made. In the north the Oxus was crossed, and a greater part of Transoxiana was occupied. In the east the frontiers were pushed up to India. In the west the whole of North Africa was conquered. From North Africa the Muslims crossed over to Spain and occupied a part thereof. In the Mediterranean the islands of Cypress and Rhodes were conquered during the reign of Uthman. Under Uthman the Muslims became a naval power for the first time. They
undertook some fifty military operations against the Byzantines. In the war against the Byzantines many forts were captured in Asia Minor. A campaign was undertaken against Constantinople itself, but it had to be abandoned because of the disturbed state of home politics.