Muslim civilization always has been mobile (moving). Both the Arabs and the conquerors from Central Asia were originally nomadic (able to move or travel around) and inherited a tradition of travel. Large armies were constantly on the move. Students and scholars went on long journeys to sit at the feet of famous teachers, for the Prophet Muhammad himself encouraged travel even “as far as China” for learning. The wealth of cities depended upon trade. And the Faith of Islam asked of the Faithful the most powerful of all reasons for travel — the Pilgrimage. So Muslims traveled the length and breadth (width) of the vast (large, extensive, widespread) Islamic Empires and beyond, especially for trade purposes. Muslims traveled by land and by sea and through their trips they began an Age of Travel and Exploration far beyond their homelands.