Ouidah in the early 18th century was a slave-trading hub where European powers competed for access to the human cargo flowing from the interior. The French had established a small trading post there in 1671, upgrading it to Fort Saint-Louis in 1704. The English Royal African Company built William's Fort in 1692. The Portuguese were the latecomers. After losing Elmina Castle to the Dutch in 1637, they had spent decades without a base on the Gulf of Guinea -- an intolerable position for a nation deeply invested in the slave trade to Brazil. In 1721, Bahia merchant Captain Jose Torres sailed to Ouidah and erected the Portuguese fort on a site chosen by the Hueda king, a few hundred yards east of the English fort. All three fortifications were built of dried mud by enslaved African laborers using local masonry methods -- roughly 100 meters square each, with earthen walls two to three meters thick, 20-foot moats, and thatch roofs that made them terribly vulnerable to fire.

The kings of Hueda, and later the kings of Dahomey who conquered the region in 1727, refused to allow European forts on the coastline. Positioned four kilometers inland, all three forts depended entirely on royal goodwill. Directors were required to travel 100 kilometers north to the Dahomean capital of Abomey each year to pay their respects during the annual festivities the Europeans called "customs" -- in reality, a ritual reminder of who held the real power. When King Tegbesu suspected the Portuguese fort director Joao Basilio of conspiring with his enemies in 1743, he had him imprisoned and expelled. Dahomean troops subsequently assaulted the fort, and the Portuguese gunpowder magazine exploded, destroying the structure entirely. It was rebuilt, but the incident illustrated a persistent truth: these European forts existed at the pleasure of African rulers, not despite them.

When Britain, France, and Portugal legally abolished the slave trade in the early 19th century, the Ouidah forts were abandoned or repurposed. The British and French forts became palm oil trading stations. The Portuguese fort sat empty. But the trade in enslaved people did not end -- it went underground. Francisco Felix de Sousa, a Brazilian-born clerk who had once worked at the Portuguese fort, became one of the most powerful illicit slave traders on the coast. He helped a younger brother of the ruling Dahomean king seize the throne as Ghezo, and in return was installed as "captain of the Whites" -- a position of extraordinary privilege. Known by his nickname chacha, de Sousa and his sons dominated Brazil's illegal slave-trading network along the Slave Coast. In 1822, he reportedly hoisted the flag of the newly proclaimed Brazilian Empire over the fort, though he conducted his operations and lived with his many wives and children elsewhere in Ouidah.

Portugal reoccupied the fort in 1865 and clung to it with remarkable tenacity. When France colonized Dahomey in the 1890s, Portuguese diplomats insisted on retaining sovereignty over the tiny enclave, now entirely surrounded by French territory. A small detachment of troops from Portuguese Sao Tome and Principe garrisoned the fort until 1911; after that, only the residente -- the governor -- his assistant, and their families remained. By the 1921 census, the fort had five inhabitants. When the Republic of Dahomey gained independence in 1960 and issued an ultimatum to Portugal in August 1961, only two Portuguese citizens remained. Rather than surrender, they attempted to burn the fort. Portugal did not formally recognize Dahomey's annexation until 1975. Today the restored fort houses the Ouidah Museum of History, its mud walls rebuilt to preserve the memory of what happened within them -- a place where the stories of enslaved people, colonial politics, and the stubborn persistence of empire converge.