<P> Following the collapse of the Songhai Empire, a number of smaller states arose across West Africa, including the Bambara Empire of Ségou, the lesser Bambara kingdom of Kaarta, the Fula / Malinké kingdom of Khasso (in present - day Mali's Kayes Region), and the Kénédougou Empire of Sikasso . </P> <P> European traders first became a force in the region in the 15th century, with the 1445 establishment of a Portuguese trading post at Arguin Island, off the coast of present - day Senegal; by 1475, Portuguese traders had reached as far as the Bight of Benin . The transatlantic African slave trade began almost immediately after based on the already well established slave trading capacity serving the Islamic world, with the Portuguese taking hundreds of captives back to their country for use as slaves; however, it would not begin on a grand scale until Christopher Columbus's voyage to the Americas and the subsequent demand for cheap colonial labour . In 1510, the Spanish crown legalised the African slave trade, followed by the English in 1562 . By 1650 the slave trade was in full force at a number of sites along the coast of West Africa, and over the coming centuries would result in severely reduced growth for the region's population and economy . The expanding Atlantic slave trade produced significant populations of West Africans living in the New World, recently colonised by Europeans . The oldest known remains of African slaves in the Americas were found in Mexico in early 2006; they are thought to date from the late 16th century and the mid-17th century . </P> <P> As the demand for slaves increased, some African rulers sought to supply the demand by constant war against their neighbours, resulting in fresh captives . States such as Dahomey (in modern - day Benin) and the Bambara Empire - based much of their economy on the exchange of slaves for European goods, particularly firearms that they then employed to capture more slaves . European and American governments passed legislation prohibiting the Atlantic slave trade in the 19th century, though slavery in the Americas persisted in some capacity through the century in the Americas; the last country to abolish the institution was Brazil in 1888 . Descendants of West Africans make up large and important segments of the population in Brazil, the Caribbean, the United States, and throughout the New World . </P> <P> African Americans in several major US cities who took part in a generic research study, concluded that their common ancestry originated most prominently in western Africa which is consistent with prior genetic studies and the history of slave trade . </P>

How did trade influence the rise and fall of the three major west african empires