Africa, like China, was not well known to the outside world before the nineteenth century, and information about the interior was the product of occasional visits from hardy travellers, such as Ibn Battuta—the Marco Polo of the tropics. However, the assumption that the continent was also isolated from external contacts, though it has served a useful purpose here in focusing attention on internal checks on the development of the market, is historically inaccurate and must now be discarded. In reality, West Africa had well-established and highly organised external commercial links across the desert and the ocean. These highways, though slow and hazardous, connected the region to the international economy centuries before the Industrial Revolution enabled the major European powers to increase their penetration of the underdeveloped world. The fact that West Africa conducted an extensive foreign commerce is clearly relevant to the theme of stability and change in the market, for it is a matter of historical experience that societies which have been inhibited by domestic constraints have sometimes discovered a path to economic development through international trade.