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Praia Melão, a sugar mill and slavery plantation, situated on São Tomé, stands as the primary focus of archaeological exploration on the island.	Source: M.D. Cruz/Antiquity Publications Ltd

Tiny West African Island Shows Evidence of the Invention of Plantation Slavery


Situated on the West coast of Africa, with the equator running through it, the tiny island of Sao Tome was uninhabited before being colonized by the Portuguese in 1486. Now being investigated archaeologically for the first time, it has exhibited evidence of being the ‘first tropical slavery plantation economy’, a model that was later taken with devastating consequences over to the Americas.

Archaeologists have been conducting a study of the Praia Melão, Sao Tome’s largest sugar mill and estate from the 16th century, and published their results in the latest edition of Antiquity. A team of researchers led by M. Dores Cruz, a historical anthropologist from the Department of African Studies at the University of Cologne in Germany, collaborated with colleagues from the University of São Tomé e Príncipe (USTP).

Praia Melão is a newly discovered estate along the northeastern coast of the island. They have applied modern archaeological techniques to analyze one of São Tomé's sugar mills. Situated adjacent to the Ribeiro Manuel Jorge, which flows eastward toward the Gulf of Guinea, the sugar mill and estate house form a single structure, to the south of Praia Melão village.

The Sao Tome ‘Model’ Sugar Colony and Slavery Plantation

Sao Tome, named after Saint Thomas, is an island situated 150 miles (240 km) to the west of Gabon in the Gulf of Guinea. The Portuguese stumbled upon uninhabited territory with an abundance of resources – timber, freshwater - and vast potential for sugarcane cultivation. The monarchy tried to encourage settlement, but due to the high prevalence of malaria, São Tomé was widely regarded as a perilous place to live.

As early as 1495, in order to provide a workforce for the burgeoning sugar trade, Portuguese authorities compelled convicts, Jewish children, and enslaved Africans to relocate to the island. By the 1530s, the São Tomé colony ascended to become the world's foremost sugar producer.

Here, enslaved people performed all functions of production – from harvesting to processing, and even stone masonry. This made it "the first plantation economy in the tropics based on sugar monoculture and slave labor, a model exported to the New World where it developed and expanded," write the authors of the study.

The workforce was driven by enslaved Africans from regions such as Benin, the Niger Delta, Fernando Po Island, Congo and subsequently, from the Kongo and Angola. It overtook the Atlantic archipelago of Madeira in supplying almost the entire European market with sugar, reports Live Science. As a result, dozens of sugar mills were built on this island.

However, by the 17th century, unable to keep up with sugar production in Brazil, the high humidity levels, and perennial slave rebellions, most of the sugar production was shifted across the Atlantic, causing most mills to fall into disuse by the 19th century.

“The European population on the island dwindled, while the Creole elite and free Black people strengthened their political and social power, controlling landownership and trade, namely in human beings destined for Brazilian and Caribbean plantations,” write the authors of the study.

Estate house and sugar mill. It symbolizes the beginning of a slavery plantation-based economic system. (M.D Cruz/ Antiquity Publications Ltd)

Estate house and sugar mill. It symbolizes the beginning of a slavery plantation-based economic system. (M.D Cruz/ Antiquity Publications Ltd)

Architecture of Habitation and the Production Process

The sugar mill at Praia Melão was examined thoroughly. At two stories high, its upper floor housed the living quarters, and the lower level functioned as a sugar boiling room, a highly labor intensive process. Here, multiple ceramic sugar molds were uncovered, resembling those found in Madeira. The building’s windows were built in such a way that workers (slaves) could be surveilled from every angle, reports a press release.

Upper floor access and graffiti noted; lower level exhibits signs of scorching. (M.D. Cruz/Antiquity Publications Ltd)

Upper floor access and graffiti noted; lower level exhibits signs of scorching. (M.D. Cruz/Antiquity Publications Ltd)

The elemental composition of the materials was determined through the use of X-ray fluorescence, a technique employed to ascertain the presence of various elements. In this particular instance, the analysis focused on three sherds of molds, revealing that they originated from the Aveiro-Ovar region in Portugal. This region was a prominent hub for ceramic production during that era.

To prepare the sugar, cane syrup was boiled in huge copper cauldrons until crystallization, and then placed into the sugar molds, which were conical in shape. This would allow the drainage of molasses, allowing the crystals to solidify. The outcome was the iconic sugar cone known as "pão de açúcar," which translates to "sugar loaf" in Portuguese.

“Parts of the building have collapsed, and floors are covered by rubble that may conceal additional features, but surviving walls are between 5m (16.40 ft) and 9m (29.52 ft) high. The upper-floor domestic areas are stuccoed, while work-area walls are roughly finished and exhibit graffiti with lettering, crosses and other religious symbols. As was common in contemporary Portuguese residences, the kitchen may have been outside, but neither it nor any slave quarters have been located,” they write.

Carrying it Across: The Transatlantic Slave Model

"São Tomé was a major nexus between Europe and Africa," state the authors, "but lack of research obscures the significance of this archipelago in the history of the Atlantic world and plantation slavery."

The formulaic and gruesome nature of the Transatlantic slave trade is well documented – as the Iberian colonizers ‘discovered’ the New World, i.e., the Americas, they chanced upon dozens of new crops that had huge commercial potential – tobacco, sugar, coffee, to name a few. The indigenous populations, with no immunity to ‘Old World’ diseases, dropped like flies, and the conquest of the Americas, though met with great resistance, was achieved with relatively less firepower.

Slaves cutting sugar cane.  (William Clark/CC0)

Slaves cutting sugar cane.  (William Clark/CC0)

To bridge the problem of labor owing to this rapidly dwindling local population, the Spanish and the Portuguese traded guns and other equipment with African warlords, predominantly along the Western Coast of Africa, in exchange for slaves. These chattel slaves were packed off in inhumane conditions on ‘slave ships’ across the Atlantic, to work on the newly emerging plantations (a whopping 2 million people died whilst making the voyage, another 2 million died working on these plantations).

The resultant understanding is that this study has the vast potential to form a blueprint to understand colonialism, particularly the plantation economies of the Iberian colonies, and subsequent European powers. In the architecture and production lie the keys to understanding the social and economic model that would determine the course of human history over the next 4 centuries.

Top image: Praia Melão, a sugar mill and slavery plantation, situated on São Tomé, stands as the primary focus of archaeological exploration on the island.            Source: M.D. Cruz/Antiquity Publications Ltd

By Sahir Pandey


Cruz, M., Thomas, L., & Ceita, M. 2023. Bitter legacy: Archaeology of early sugar plantation and slavery in São Tomé. Antiquity. Available at: https://doi:10.15184/aqy.2023.113.

Killgrove, K. 2023. Plantation slavery was invented on this tiny African island, according to archaeologists. Available at:

Liberatore, S. 2023. First-ever slavery plantation is discovered in Africa: Ruins of a nearly 500-year-old sugar mill and estate located on a tiny island to the west. Available at:

Mitchell, A. 2023. Plantation slavery took root on African island before expanding to New World. Available at:



A reasonably balanced article.

Sahir's picture


I am a graduate of History from the University of Delhi, and a graduate of Law, from Jindal University, Sonepat. During my study of history, I developed a great interest in post-colonial studies, with a focus on Latin America. I... Read More

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