Motivated by the desire for new markets and an ongoing opposition to the Muslims, Portuguese sailors had begun to explore the West African coast in the first half of the fifteenth century. The expeditions were sponsored by Prince Henry of Portugal, who founded a center for seamanship around 1420 and earned himself the title of the Navigator. At the center, information about tides and currents was collected, more accurate charts and maps were drawn, techniques for determining longitude were improved, and new ship designs (such as the caravel) were developed. With these innovations, the Portuguese reached the westernmost point of the continent at Cape Verde in 1448, setting up a lucrative network of trading posts along the way. The most significant voyages, however, came forty years later. Bartolomeu Dias rounded the Cape of Good Hope at the southern tip of Africa in 1488. A decade later, Vasco da Gama sailed around Africa and reached the Malabar Coast of India, establishing an all‐water route to Asia. Over the next twenty years, Portugal made Goa its major trading center in India, established outposts in Malaysia, and set up direct contact with China. The Muslim monopoly on the spice trade in Asia was broken.
The West African kingdoms. One consequence of the Portuguese expeditions was contact with West Africa. The sub‐Saharan kingdoms—Ghana, Mali, Benin, Songhai, and Kongo—were well‐organized societies with a long history, but they were almost unknown to Europeans. Until the Muslim invasions of the eleventh century, the Ghana empire had extensive commercial ties with North Africa, Egypt, and the Middle East. Mali, an Islamic state whose capital Timbuktu was a major economic and cultural center, controlled the gold trade. The arrival of the Portuguese brought about a dramatic shift in the flow of African gold. Rather than going overland by caravan to North Africa and then into the coffers of the commercially powerful Italian city‐states, the precious metal was shipped by sea directly to Lisbon and western Europe.
The Portuguese were interested in slaves as well as gold. Arab merchants had bought slaves in West Africa as early as the eighth century, and they continued to act as middlemen when the Europeans arrived. Portugal used African slaves as early as 1497 in the sugarcane fields on the islands it took over off the African coast. Millions of blacks were shipped from West African ports to work plantations in North and South America over the next three hundred years. Slavery in the New World, justified on economic and racial grounds, was quite different from that in Africa. Although slavery was an accepted social institution throughout the continent, the slaves were typically prisoners of war, debtors, or criminals, and their condition was neither permanent nor hereditary.