After Portuguese navigators found the islands uninhabited (c. 1470), the crown began organized settlement in the late 1400s. Early colonization relied heavily on coerced migrants—including convicts and deported Jewish children—and the importation of enslaved Africans, setting up a labor system geared toward export crops.
By the early 1500s, São Tomé’s administrators promoted sugarcane as a high-value crop, drawing on Atlantic island experience (such as Madeira). Contemporary observers described large cane fields by about 1506, showing that the colony was being reorganized around plantation-style agriculture and processing.
Sugar expansion quickly increased demand for labor. Portugal imported enslaved Africans to São Tomé in large numbers in the early 1500s, tying plantation growth directly to slave-raiding and slave markets on the West and Central African coasts.
During the 16th century, São Tomé briefly became one of the world’s major sugar producers. The islands became a testing ground for the plantation-and-mill system—large estates, centralized processing, and forced labor—that would later be replicated on a much larger scale in the Americas.
As sugar and slavery expanded, many enslaved people escaped into the island’s interior. These maroon communities (runaway settlements) and their raids on estates increased insecurity and costs for plantation owners, weakening the sugar economy over time.
On 9 July 1595, a large revolt led by Rei Amador mobilized enslaved workers and allied groups against Portuguese rule. The rebellion destroyed plantations and mills and nearly overran the island, demonstrating that plantation slavery faced sustained resistance as well as economic limits.
Portuguese forces eventually suppressed the uprising. Amador was captured on 4 January 1596 and executed, and the revolt is widely linked to lasting damage to the sugar plantation system on the islands.
By the late 1500s and early 1600s, São Tomé’s sugar industry deteriorated. Major causes included rising competition from Brazil and continuing social instability, which reduced profitability and made plantation operation harder to sustain.
In 1641, Dutch forces briefly captured São Tomé during wider Dutch-Portuguese conflicts in the Atlantic world. The occupation and later Portuguese recovery underscored how strategic the islands were for trade routes, even after sugar’s peak.
After the collapse of sugar, São Tomé and Príncipe increasingly served as an Atlantic staging point for the Portuguese slave trade to Brazil. Smaller ships carrying captives could be reorganized and provisioned before the longer transatlantic crossing, keeping the islands linked to slavery even as sugar fell.
In the 1830s, Portugal faced growing international pressure to end the transatlantic slave trade. A major turning point came with the 1836 abolitionist decree associated with Sá da Bandeira, which aimed to suppress the slave trade in Portuguese territories and signaled a shift in official policy, even if enforcement was uneven.
Pressure to enforce anti–slave-trade measures increased across the Atlantic in the mid-1800s, reducing the ability of ports and islands to operate openly in human trafficking. This broader suppression helped push São Tomé and Príncipe further away from being a major slave-trade waystation, although forced labor systems did not disappear.
By 1850, the earlier sugar-and-slavery plantation complex that made São Tomé a major early sugar producer had long been broken by revolt, flight, competition, and shifting trade roles. The islands remained shaped by coerced labor and plantation landholding, but the center of gravity was moving toward new crops and new labor regimes later in the 19th century.
Sugar and slave-linked plantation complex in São Tomé and Príncipe (1506-1850)