A map of Africa today is shown; the sub-Sahara region, not including South Africa, is where the European slave traders were active. The Portuguese began dealing in black slaves from Africa in the 15th century. Initially, they purchased slaves from Islamic traders, who had established inland trading routes to the sub-Sahara region. Later, as the Portuguese explored the coast of Africa, they came upon the Senegal River, and found that they could purchase slaves directly from black Africans. The European slave trading activity moved south along the African coast over time, as far south as Angola. On the east coast of Africa and in the Indian Ocean region, slaves were also taken from Mozambique, Zanzibar and Madagascar. Many of the slaves were from the interior of Africa, having been taken captive as a result of tribal wars, or else having been kidnapped by black slave traders engaged in the business of trading slaves for European goods. These slaves would be marched to the coast to be sold, sometimes traveling hundreds of miles. Many perished along the way - the numbers can only be estimated. Lovejoy (20) notes that losses on the ships were estimated at 9-15 per cent, and losses at Dutch-ruled Cape Coast castle were reported to be 6-7 per cent. Losses from the point of capture to the point of arrival at the slave trading forts were estimated to be 40% by Miller (21) based on data from Angola. Using Thomas' (12) figure of 11,128,000 live slaves delivered to the New World during the Atlantic slave trade, and considering Lovejoy's and Miller's estimates of losses, the number of captured slaves in the interior of Africa is estimated to be from 21.7 million to 23.5 million people. This figure does not include the many who may have been killed in the process of capture.