Roça Sundy is one of those places where the great history of the world passed through a remote corner: on this cocoa plantation in northwest Príncipe, on 29 May 1919, the British astronomer Arthur Eddington photographed a total solar eclipse and obtained the proof that confirmed Einstein's Theory of General Relativity. That observation, made on an African island lost in the Atlantic, changed our understanding of the universe forever.
But Sundy is much more than a scientific milestone. Founded in the early 19th century, it was one of the country's first and largest cocoa plantations, with its manor house, hospital, chapel and rows of workers' housing: a classic 'roça' from the era when São Tomé and Príncipe was the world's largest cocoa producer. Today, restored by the HBD group, it is a charming hotel that keeps its plantation soul and offers 'tree-to-bar' cocoa tours.
This guide tells Sundy's double story —that of cocoa and that of the eclipse—, how to visit it, what to see at the roça and its small science centre, and how to combine it with Príncipe's beaches and rainforest. It is an essential stop for understanding the island: its colonial past, its present of sustainable tourism and that astonishing moment when world science looked to the sky from this secluded corner of Africa.
Roça Sundy was founded in the early 19th century and was the first large cocoa plantation in São Tomé and Príncipe, in the era when the country became the world's largest producer of 'brown gold'. Its great historic moment came on 29 May 1919, when the astronomer Arthur Eddington observed from its grounds the total solar eclipse that confirmed Einstein's Theory of General Relativity. The manor house, built in 1921, was restored by the HBD group and is today a charming hotel with cocoa tours, on an island declared a UNESCO Biosphere Reserve in 2012. The full story is told on our history page.
Read the full history ↓The country's greenest and most unspoilt island: an autonomous region and biosphere reserve, with a forgotten town that was once the colonial capital, and the roça where Einstein's relativity was confirmed.
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Origins, formation and what the sources say.
Roça Sundy was established in the early 19th century in the northwest of the island of Príncipe, and is considered one of the first and largest cocoa plantations in São Tomé and Príncipe. A territorial map from 1814 already showed the estate, which had a chapel dedicated to Our Lady of France. Over time, coffee and coconut were grown at Sundy as well as cocoa, and the estate grew very large, with its own hospital for owners and workers.
Sundy is a textbook example of a 'roça', the institution that defined São Tomé and Príncipe for more than a century: a plantation-village organised around the 'casa grande' (the manor house), with its hospital, chapel, drying yards, warehouses and 'sanzalas', the rows of workers' housing. Everything revolved around producing cocoa, the 'brown gold' that made the archipelago's fortune.
In the early 20th century, São Tomé and Príncipe became the world's largest cocoa producer, and roças like Sundy were at the heart of that dominance. But the system rested on the gruelling work of the 'serviçais', contract labourers brought from Angola, Cape Verde and Mozambique in conditions so close to slavery that, around 1909, they led to a boycott by British chocolate makers and an international scandal over 'slave cocoa'.
In 1915, Albert Einstein had formulated his General Theory of Relativity, which put forward a revolutionary idea: gravity is not a force in Newton's sense but a curvature of space-time, so starlight should bend when it passes close to a massive body such as the Sun. Testing it required a total eclipse: only with the Sun blocked out could the stars near its edge be photographed and their apparent position measured to see if it had shifted.
The total solar eclipse of 29 May 1919 offered that chance, and British astronomer Arthur Eddington led one of the two expeditions sent to observe it. Eddington chose Roça Sundy, on the island of Príncipe, for its clear skies and its location within the path of totality. He set up his instruments on the plantation grounds and, despite the clouds, managed to photograph stars of the Hyades cluster around the eclipsed Sun.
By comparing the position of those stars during the eclipse with their usual position, Eddington found the slight shift Einstein had predicted: the light had bent as it passed the Sun. The announcement of the results, in late 1919, caused a worldwide sensation: it confirmed general relativity experimentally and made Einstein famous across the globe. That such a milestone in physics was achieved from a remote cocoa plantation in the Gulf of Guinea is one of the great curiosities in the history of science.
The manor house you see at Sundy today was built in 1921 by the Carneiro family, owners of the roça, a few years after the famous eclipse. During the first decades of the 20th century, the plantation remained an important centre of production in a country that lived almost entirely off cocoa and coffee exported to Europe.
But over the course of the 20th century cocoa went into a long decline, due to competition from other producers, soil exhaustion and lack of investment. After São Tomé and Príncipe gained independence from Portugal on 12 July 1975, many roças were nationalised and then fell into neglect, their manor houses crumbling and the forest reclaiming the cocoa groves. Sundy, like so many others, went into decline.
For decades, descendants of the plantation workers went on living in Sundy's old 'sanzalas', in precarious conditions. The roça stayed inhabited but half-abandoned, its scientific and economic glory reduced to a memory. Its revival would only come well into the 21st century, driven by sustainable tourism and a renewed appreciation of the island's historical heritage.
The turning point came with HBD, the company of South African tech entrepreneur Mark Shuttleworth, which bet on Príncipe as a sustainable luxury tourism destination and on restoring its heritage. HBD restored the 1921 manor house and turned it into one of the island's most charming and historic hotels, part of the Príncipe Collection project alongside Sundy Praia and Bom Bom. Around 2024, the company also funded new homes for the residents of the old sanzalas, relocating them to better conditions.
Roça Sundy thus regained a double life. On one hand, it became a working cocoa plantation again, offering visitors 'tree to bar' tours: the full journey from the pod to the chocolate, with a tasting, reviving the island's cocoa tradition to modern standards. On the other, the roça embraces its scientific heritage: the 'Espaço Ciência e História Sundy' was created, a centre that uses images and maps to explain the 1919 eclipse and the confirmation of relativity.
In 2019 the eclipse centenary was marked with international events, reaffirming Sundy's place in the history of science. Today, on an island declared a UNESCO Biosphere Reserve in 2012, Roça Sundy sums up Príncipe's past and present like few other places: the memory of cocoa and the harsh conditions on the roças, the astonishing eclipse that proved Einstein right, and today's commitment to tourism that preserves heritage and nature.
