King Willem-Alexander has formally apologised for the Netherlands’ slave trading history at the commemoration of the abolition of slavery in Amsterdam.

“On December 19 last year the prime minister offered his apologies in the name of the Dutch government for the fact that for centuries people were reduced to commodities, exploited and abused, in the name of the Dutch state,” he said.

“Today I stand before you. As your king and as part of the government, I make those apologies myself.”

Cheers went up from the crowd at the Keti Koti ceremony in Oosterpark as the king spoke the words, which follow decades of campaigning to recognise the legacy of slavery.

The king’s statement had been widely anticipated after prime minister Mark Rutte apologised last December and promised a “comma, not a full stop”, signalling that the discussion needed to continue.

The king contrasted the situation in Amsterdam, which issued a declaration in 1644 that all people in the city were free “and no slaves”, with the lives of people transported across the Atlantic to the colonies.

“Degrading and dehumanising”

“What was taken for granted in this city and this country did not apply beyond our borders,” he said. “Slavery was forbidden here, but not there.”

“Of all the ways to be unfree, slavery is the most hurtful, the most degrading and the most dehumanising.”

The king said he and Queen Maxima had spoken to people in the Caribbean nations and whose roots are in Suriname and Indonesia to better understand the impact of slavery on their lives. “They have made clear to us how deeply the pain still runs through their veins,” he said.

He acknowledged that some people felt apologising for slavery more than a century after the event was an “exaggerated” response, but still wanted to build a more equal society.

“That’s why I ask you to open your heart to all those people who are not here today, but who want to work with you towards a society in which everyone can play their full part,” he said. “Respect the fact that there are difference in experience, background and perspective.”

This year’s Keti Koti ceremony, which marks the 150th anniversary of the abolition of slavery in Suriname, was accompanied by a festival on Museumplein where the king’s speech was livestreamed.

Keti Koti – which means “the chains are broken” in the Surinamese language Sranantongo – has been commemorated every year in Amsterdam on July 1 since the national memorial to slavery was put up in the park in 2002. It has been a national holiday in Suriname and the Antillean islands since 1863.

“Healing process”

A study into the royal family’s own role in the slave trade, commissioned by the king as part of what he called a “healing process”, concluded that the house of Oranje-Nassau earned the equivalent of €545 million in today’s money from slavery, exploitation and forced labour.

Rutte and Queen Maxima also attended the ceremony in the Oosterpark, along with finance minister Sigrid Kaag and Franc Weerwind, the minister for legal protection, who has Surinamese ancestry.

Several other ministers were present at ceremonies in the Dutch Caribbean nations. Foreign affairs minister Wopke Hoekstra is in Suriname, health minister Ernst Kuipers is in Curaçao, housing minister Hugo de Jonge is on the island of Bonaire, asylum minister Eric van der Burg is on Aruba and Alexandra van Huffelen, junior minister for kingdom relations, is travelling between Sint-Maarten, Saba and Sint-Eustatius.

Monuments unveiled

Two monuments to slavery are being unveiled in Utrecht and Almere, taking the total around the country to eight, while the municipalities of Middelburg and Vlissingen, which were important trading ports in the 17th century, will issue formal apologies.

An unofficial memorial was placed in Vlissingen’s harbour on Friday by campaigners after the municipal council refused to sanction one, arguing it would be “gesture politics”.

In the last two years year the mayors of all four major cities have apologised for their role in facilitating the slave trade, while the Dutch central bank (DNB) has published a report detailing how it was founded with capital from colonial entrepreneurs and provided financial services to slave traders.

DNB chairman Klaas Knot said it was important to make history visible and recognise the suffering that the bank’s activities caused. “The facts that emerged from the study and the deeply racist beliefs that underlie them affect us deeply,” he said.