The Arabs in pre-Islamic times were not entirely unacquainted with the sea. For centuries before the rise of Islam the peoples of southern Arabia built ships and carried on important maritime traffic in the Red Sea and Indian Ocean. But the northern Arabs, and particularly those of the Hijaz and of the Syrian and Iraqi borderlands, were primarily a continental people, with little knowledge of the sea or of navigation.
It is one of the most striking features of the great Arab conquests that they should have adapted themselves so readily to this new form of activity. Within a few years of their control of the Syrian and Egyptian coastlines the people of the landlocked deserts of Arabia, with the help of local shipwrights and sailors, had built and manned great war fleets which were able to meet and defeat the powerful and experienced Byzantine navies and to give to the Caliphate that vital prerequisite of its safety and expansion — the naval control of the Mediterranean.