and Benguela (a fort from 1587, a town from 1617) remained almost continuously in Portuguese hands. As in Guinea, the slave trade became the basis of the local economy in Angola. Excursions traveled ever farther inland to procure captives who were sold by African rulers; the primary source of these slaves were those captured as a result of losing a war or interethnic skirmish with other African tribes. More than a million men, women, and children were shipped from Angola across the Atlantic. In this region, unlike Guinea, the trade remained largely in Portuguese hands. Nearly all the slaves were destined for the Portuguese colony of Brazil. In Mozambique, reached in the 15th century by Portuguese sailors searching for a maritime spice trade route, the Portuguese settled along the coast and made their way into the hinterland as sertanejos (backwoodsmen). These sertanejos lived alongside Swahili traders and even obtained employment among Shona kings as interpreters and political advisers. One such sertanejo managed to travel through almost all the Shona kingdoms, including the Mutapa Empire's (Mwenemutapa) metropolitan district, between 1512 and 1516. By the 1530s, small bands of Portuguese traders and prospectors penetrated the interior regions seeking gold, where they set up garrisons and trading posts at Sena and Tete on the Zambezi River and tried to establish a monopoly over the gold trade. The Portuguese finally entered into direct relations with the Mwenemutapa in the 1560s. However, the Portuguese traders and explorers settled in the coastal strip with greater success, and established strongholds safe from their main rivals in East Africa – the Omani Arabs, including those of Zanzibar. Scramble for Africa and the World Wars Portugal's colonial claim to the region was recognized by the other European powers during the 1880s, during the Scramble for Africa, and the final boundaries of Portuguese Africa were agreed by negotiation in Europe in 1891. At the time, Portugal was in effective control of little more than the coastal strip of both Angola and Mozambique, but important inroads into the interior had been made since the first half of the 19th century. In Angola, construction of a railway from Luanda to Malanje, in the fertile highlands, was started in 1885. Work began in 1903 on a commercially significant line from Benguela all the way inland to the Katanga region, aiming to provide access to the sea for the richest mining district of the