At least 3.3 million people were enslaved by the Netherlands during the transatlantic slave trade, according to new research.
This figure is more than five times the widely cited estimate of 600,000.
The previous data was used in official apologies by King Willem-Alexander and former Prime Minister Mark Rutte.
Investigative journalist Leendert van der Valk argues that the widely accepted number is a gross underestimation.
Van der Valk's book indicates the true number of victims lies between 3.3 and 5.3 million.
The historical gap exists because previous calculations omitted various colonised regions, long-term involvement, and generations born into enslavement.
Humanizing the Victims
Peggy Brandon, a Surinamese-born cultural leader and curator of the developing National Museum of Slavery, stressed the importance of accurate numbers.
She said the metrics matter deeply for humanising the victims.
“What upsets me is that we never talk about the people who lived generation after generation within that system of enslavement,” Brandon said.
“We don’t talk about the people who sometimes killed their young children because they didn’t want them to grow up in enslavement.”
Brandon explained that establishing the true scale challenges persistent colonial narratives. It honors individuals previously overlooked by history.
“It’s going back to the fact that these were human beings. And every person has a right to be seen and to be known,” she said.
Expanding Historical Parameters and Geography
The updated calculations rely on demographic research from Radboud University.
Matthias van Rossum, a colonialism professor at Radboud and the International Institute of Social History, explained the shifting perspective.
“The new figures … rightfully shift the question from its narrow focus on the numbers of enslaved people displaced directly through long-distance slave trade to including those enslaved who were born in slavery or enslaved in other ways,” Van Rossum said.
Van der Valk's research covers regions like South Africa, India, and Sri Lanka, which were major Dutch territories before British rule.
It also includes Caribbean territories such as Guyana and Tobago, which remained Dutch until 1814.
The book argues that the historical timeline of Dutch involvement should start from 1595 rather than 1630.
It also argues the timeline should extend to 1914, when enslavement ended in parts of Indonesia, instead of the official abolition date of July 1, 1863.
Coen van Galen, an associate professor in colonial history at Radboud, described the calculation as a rough estimate.
He said it provides the first comprehensive indication of total victims across all Dutch colonies combined.
“Based on this work, comparable calculations could also be undertaken for the British empire and other colonial empires,” Van Galen said.
“Such estimates would, for the first time, provide a more comprehensive picture of the total number of people worldwide who were victims of colonial slavery.”
The publication emerges as black communities and Dutch territories urge Prime Minister Rob Jetten to follow up previous apologies with concrete action.
This aligns with a recent United Nations resolution declaring the trafficking of enslaved Africans as a grave crime against humanity.
