Long-distance trade played a major role in the cultural, religious, and artistic exchanges that took place between the major centers of civilization in Europe and Asia during antiquity. Some of these trade routes had been in use for centuries, but by the beginning of the first century A.D., merchants, diplomats, and travelers could (in theory) cross the ancient world from Britain and Spain in the west to China and Japan in the east. The trade routes served principally to transfer raw materials, foodstuffs, and luxury goods from areas with surpluses to others where they were in short supply. Some areas had a monopoly on certain materials or goods. China, for example, supplied West Asia and the Mediterranean world with silk, while spices were obtained principally from South Asia. These goods were transported over vast distances— either by pack animals overland or by seagoing ships—along the Silk and Spice Routes, which were the main arteries of contact between the various ancient empires of the Old World. Another important trade route, known as the Incense Route, was controlled by the Arabs, who brought frankincense and myrrh by camel caravan from South Arabia.