Final answer:
Islam was firmly established as a religion in Ancient Mali as early as the 14th century through trade and migration. The influence of Islam spread throughout West Africa up until the 18th century.
Step-by-step explanation:
Islam was firmly established as a religion in Ancient Mali as early as the fourteenth century. As in other parts of the world, Islamic conversion occurred through trade and migration far more often than by force. In West Africa, prior to the eighteenth century, much of this conversion occurred through interaction of West Africans with Berber traders who controlled the trans-Saharan trade routes. From the early seventeenth century through the late eighteenth century, the influence of Islam spread among the people in many parts of the Senegambia region, the interior of Sierra Leone, the Gold Coast and as far south as the Bight of Benin.