Human history is believed to have begun in Africa, probably in the eastern and southern part of the continent,as human ancestors evolved into the species homosapiens , perhaps 200,000 years ago, and began peopling the sub-Saharan region. (1) About 50,000 to 100,000 years ago, according to most current scientificthinking, small bands of these fully modern humans crossed out of Africa into the Middle East, and became theancestors of all human populations elsewhere. (2) An internal African migration of great significance was launched perhaps 2,500-5,000 years ago, as the Bantu people of West Africa began to expand their area ofsettlement from a base that was probably in the northeast of present-day Nigeria or possibly Cameroon. The Bantueventually became the predominant peopleover most of sub-Saharan Africa, although people speaking so-called Nilo-Saharan languages are widely found inthe Sahel grasslands on the southern border ofthe Sahara and parts of eastern Africa. The Nilo-Saharan languages may have had their origins in the Nile valley,but the term "Nilotic" to describe peoplesexisting today has fallen out of favor with scholars because of the extensive intermingling of Bantu andNilo-Saharan speakers over the centuries. Bantu tropicalagriculture was not suited to the Mediterranean climate of extreme southern Africa, and this region continued to beinhabited by people known as "Khoisan" or"San." Experts are uncertain about the origins of iron use in Africa, (3) but by about 500 BC, it appears that the Bantu had become skilled in smelting iron and making theiron tools that created a highly successful agriculture and accelerated their expansion. When Europeans began toexplore the African coast after 1450 AD, theyfound that farmers were growing a wide variety of crops, including grains as well foods unfamiliar to Europeans,such as bananas. Some of these had come intoAfrica through contacts with the Indian Ocean region and southeast Asia. (4) Many African farmers also had cattle, although the tsetse fly kept cattle outof thewetter, central part of the continent. After the discovery of America, farmers quickly adopted New World crops,such as maize and peanuts. By 1500, an estimated 47 million Africans were living in thousands of farming communities spread across the continent, (5) although in particularly dry regions,such as Kenya's Rift Valley, some lived a purely pastoral life, herding cattle, sheep, and goats. These wereexchanged with farmers for grains and otheressentials. (6) Large towns and cities had notdeveloped, probably because large settlements were likely to be struck down by the parasites and otherdisease-causing organisms that had evolved with homo sapiens in Africa. (7) Human populations outside Africa, by contrast, had largely escaped thesediseasesand hence could more easily build cities. There is wide agreement among Africanists that loyalties to large ethnic groups, such as "the Yoruba" in present-day Nigeria or "the Tutsi" of east Africa, werelargely absent in pre-colonial Africa, even though they are a dominant feature of African politics today. (8) Broadly similar languages were spoken over wideareas,and these language areas may have correlated with similar cultural practices and religious beliefs as well. Buthistorians believe that Africans did not perceive thatthey had common interests with other members of these large, amorphous groups. Instead, African loyalties wereembedded in extended families, clans, andpatron-client relationships which offered protection and economic support. Some areas saw the emergence ofpowerful individuals or chiefs, sometimes termed"big men" by scholars, who exercised influence over wide areas through marriage ties and other means, such ascontrol over a critical trade route. (9) A number of African kingdoms developed as the more successful chiefs consolidated their authority through conquest and alliance. To the south of the CongoRiver estuary, for example, European explorers encountered the Kongo kingdom, where a powerful king ruledseveral provinces through royal relatives. (10) Greatartistic achievements also characterized many of these pre-colonial kingdoms, as evidenced by the naturalisticbronze castings of heads in the kingdom of Benin,in today's Nigeria, and the stylized Congolese masks and carvings that inspired Picasso and other modern artists. The Atlantic slave trade is said to have begun in 1441, when a man and a woman were captured on the coast of Western Sahara and taken to Portugal. (11) Duringthe 400 years that the trade lasted, between 10 million and 13 million people were taken from Africa, according toauthoritative estimates, (12) with most going toBrazil and the Caribbean, and smaller numbers sent to the United States or the British North American colonies thatpreceded its formation in 1776. The peak ofthe trade occurred in the eighteenth century, as plantation agriculture expanded in the Americas. Annual totalsreached 100,000 in some years late in thecentury, (13) at a time when 3,000-4,000 were alsobeing taken from East Africa in the lesser-known Indian Ocean slave trade. (14) In 1807, the British parliament voted to end the slave trade, and over the next 60 years, the Royal Navy intercepted more than 1,600 ships off Africa's coasts andfreed over 160,000 captives, sending most to Sierra Leone. (15) But many ships evaded the British patrols, and large numbers of slaves continued to be exporteduntil slavery was abolished throughout the Americas in the 1850s and 1860s. U.S. participation in the slave tradewas banned by legislation passed in 1807 andstrengthened in 1819. For a number of years, U.S. Navy ships were stationed off the African coast to participatein efforts to halt the trade, but with limitedsuccess. (16) The Atlantic slave trade was conducted by European traders based on the West African coast. They purchased slaves from African owners by trading guns,alcohol, cloth, or other European-manufactured goods; as well as cowrie shells, which had monetary value inpre-colonial Africa. Slavery had long been practicedin Africa, where it was customary to enslave people captured during wars, together with condemned criminals, and,in some societies, convicted adulterers andenemies of the king. (17) In addition, some of thosesold into the Atlantic slave trade were kidnap victims. (18) According to historians, slaves in traditional Africansocieties were typically absorbed into families or local armies, and their treatment was generally less harsh than inthe plantations of the New World. Moreover,the children of slaves in Africa often could not be sold. (19) Effects. Scholars debate the effects of the slave trade on the politics and economies of African societies, (20) butthe era was clearly associated with turmoil and outbreaks of war affecting much of West Africa. The guns thatflooded Africa in exchange for slaves helped fuelthis instability, and the quest for European arms gave warring parties a powerful incentive to constantly seek newcaptives. (21) It seems certain that warfare relatedto the slave trade, the loss of millions of people in their most productive years, and the psychological damage toindividuals resulting from political instability andfear of capture, weakened Africa and left it ill-prepared to cope with the onset of direct European colonization. As late as 1870, there was little indication that the European powers were about to leave their isolated positions on the coast and partition Africa amongthemselves. Instead, it seemed more likely that indigenous political entities would consolidate their authority andeventually develop into nation-states. In WestAfrica, for example, the kingdom of Ashanti (Asante) had profited from its wealth in gold and the slave trade, andhad acquired a strong central government, anadvanced system of roads, well defined boundaries, and a national language. (22) It seemed destined to grow stronger. Buganda in East Africa, to takeanotherexample, had become the chief naval power on Lake Victoria and was known for its powerful king, the Kabaka;its strong army; and its growing trade. (23) Meanwhile, a number of "secondary empires" -- secondary in the sense that they relied on imported European military technology -- were emerging. (24) Manyofthese were based in Muslim societies, and their gains did much to promote the spread of Islam in sub-SaharanAfrica. In earlier centuries, Islam had beenspreading slowly in West Africa as a result of trans-Sahara trade contacts, and had made larger gains in northeasternAfrica through trade and Arab immigration. Africans who wanted to associate themselves with the wider Islamic world often converted willingly, and Koranicschools had begun to introduce literacy inArabic across the Sahel. But in the nineteenth century, a series of holy wars or jihads created a vastWest African Islamic empire centered on Sokoto, in modernNigeria. In East Africa, the sultans of the island of Zanzibar were extending their power on the mainland, and Egyptwas expanding its control in northeasternAfrica. With troops on Lake Victoria by 1876, (25) it seemed headed for an empire reaching into central Africa. In southern Africa, it was the "Boers" or Afrikaners, practicing a very conservative form of Christianity, who established a nineteenth century secondary empire. Descended from Dutch, Huguenot, and German settlers who had arrived at the Cape of Good Hope in theseventeenth and eighteenth centuries, thousands ofBoers trekked deep into the African interior to escape the cultural influences of the British.