Portugal captured the North African port of Ceuta, a major trading crossroads for goods moving between the Mediterranean and trans-Saharan routes. Control of Ceuta helped Portugal gather intelligence about West African trade, including gold, and encouraged further exploration down the Atlantic coast. This conquest is often treated as a starting point for Portugal’s outward expansion into Africa.
As Portuguese ships pushed farther down the West African coast, they built a fort-and-warehouse on Arguin Island to support trade and protect shipping. This created a more permanent base for exchanging European goods for African products, including gold dust, and it helped normalize the “factory” model (a fortified trading post). Arguin also became linked to early Portuguese slave trading alongside other commerce.
Pope Nicholas V issued Dum Diversas, which Portuguese rulers and later writers treated as religious-legal support for war and domination against non-Christian peoples in targeted regions. The bull mattered politically because it helped Portugal justify exclusive overseas expansion and coercive practices in Africa. It formed part of a broader set of documents later cited in European debates over who had the right to trade and rule abroad.
The papal bull Romanus Pontifex confirmed Portuguese claims to explore and trade along parts of the African coast and sought to discourage other Christian powers from interfering. In practice, it strengthened Portugal’s argument for a protected commercial sphere in regions associated with gold and other valuable commodities. This ideological and legal backing supported Portugal’s push to control coastal access to West African trade networks.
Prince Henry (“the Navigator”) died after decades of sponsoring and organizing Portuguese voyages along the West African coast. His projects had already linked exploration to profit, including gold dust and enslaved people brought to Portugal. After his death, the Crown increasingly used leases and monopolies to finance further exploration and trade control.
King Afonso V leased the Guinea trade to the Lisbon merchant Fernão Gomes in exchange for annual payments and a requirement to explore new stretches of coastline each year. The contract shows how the Portuguese Crown used private capital to expand reach while trying to keep profits and control centralized. This arrangement helped speed up Portuguese contact with regions connected to the gold trade.
Portuguese expeditions reached the area later known as the Gold Coast and encountered an established local gold trading economy. This was a turning point because it connected Portugal more directly to major West African gold flows instead of relying mainly on indirect routes. The discovery also set the stage for building a fortified hub to concentrate and protect Portuguese trade.
Portugal and Castile signed the Treaty of Alcáçovas to end a wider conflict, and it also addressed overseas competition. The settlement recognized Portuguese control over key Atlantic island groups and affirmed Portuguese rights tied to navigation and trade in areas such as Guinea, while Castile retained the Canary Islands. This reduced immediate Iberian rivalry over West African commerce, including gold-linked trade routes.
Pope Sixtus IV issued Aeterni regis, confirming earlier bulls and backing Portugal’s claims to exclusive rights in Guinea. By linking papal authority to treaty commitments, the bull strengthened Portugal’s diplomatic position when other Europeans showed interest in West African trade. This support came just as the Portuguese Crown prepared to build a major fortified base on the Gold Coast.
Portugal built Castelo de São Jorge da Mina (Elmina Castle) as a fortified factory to secure access to gold and manage trade on the Gold Coast. The fort made Portuguese commerce more regular and defensible by concentrating storage, negotiation, and shipping in one protected harbor. Over time, this coastal strongpoint also became entangled with expanding Atlantic systems of forced labor, linking gold trade infrastructure to broader imperial expansion.
Spain and Portugal agreed to the Treaty of Tordesillas, adjusting a papal dividing line for overseas claims. While best known for implications in the Americas, the treaty also mattered for Portugal’s ability to defend its Atlantic routes and African trading priorities against Spanish competition. It helped Portugal focus on consolidating networks that included West African gold trading hubs such as Elmina.
Portugal suffered a major defeat in Morocco at the Battle of Three Kings, where King Sebastian died without an heir. The loss weakened Portugal’s finances and leadership at a time when its empire depended on protected trade routes and forts, including those in West Africa. The resulting succession crisis soon brought Portugal under Spanish rule, changing how Portuguese overseas holdings were governed and defended.
After the succession crisis, the Spanish king Philip II became king of Portugal, creating the Iberian Union. Portugal’s empire, including West African forts tied to gold trade, was now linked to Spain’s wider wars and rivalries, especially with the Dutch and English. This increased strategic pressure on Portuguese coastal positions and made defending trade monopolies more difficult.
Moroccan forces defeated Songhai at the Battle of Tondibi, a decisive event in the invasion that led to the collapse of the Songhai Empire. Because Songhai had controlled key Sahel trading cities and routes, its breakdown reshaped regional power and disrupted parts of trans-Saharan commerce linked to gold. These shifts added to longer-term changes that increasingly favored Atlantic coastal trade patterns—where Portuguese forts sought to channel gold and other commodities.
West African Gold Trade and Portuguese Expansion (1450–1600)