Slavery and the Castles of the Gold Coast

On January 19, 1482, a Portuguese fleet of ten caravels and two transport ships carrying 600 soldiers, 100 masons, and pre-cut stone from Portugal anchored at a rocky promontory on the Gold Coast. Captain Diogo de Azambuja had been dispatched by King João II to build the first permanent European structure in sub-Saharan Africa: São Jorge da Mina, which the world would come to know as Elmina Castle. The site had been identified by navigators João de Santarém and Pedro Escobar, who reached the coast in 1471 and found such abundant gold that they named it 'A Mina' — the Mine.

The Portuguese extracted an estimated 24,000 ounces of gold annually from the region by the early 1500s (historian John Vogt's calculation), establishing Elmina as the most profitable trading post in the Portuguese maritime empire. A chapel added in 1503 became the first Christian church in tropical Africa. But the lucrative gold trade soon attracted rivals. The Dutch West India Company (WIC), flush with capital from Amsterdam's financial markets, laid siege to Elmina in 1637. After a bombardment from the nearby hill of St Jago, the Portuguese garrison of 35 men surrendered to Colonel Hans Coningck on August 29, ending 155 years of Portuguese control. The Dutch immediately began converting the castle's lower chambers into slave dungeons, marking the Gold Coast's transition from gold to human cargo.

By the mid-17th century, seven European nations — Portugal, the Netherlands, Britain, Denmark, Sweden, Brandenburg-Prussia, and France — had built or captured fortifications along just 500 kilometres of coastline. No comparable concentration of European military architecture existed anywhere else in Africa, a testament to the Gold Coast's extraordinary economic significance.