This set-piece speech was the most important moment of the King’s trip.
It is his first meeting of Commonwealth leaders as head of the Commonwealth.
But although the theme of this year’s meeting in Samoa talks of a “common future”, there are deepening divisions within the Commonwealth.
Reparations for the slave trade remain an issue threatening an existential crisis among the so-called family of nations.
The King said he understood how “the most painful aspects of our past resonate, it is vital we understand our history to guide us to make the right choices in our future”.
And he added: “None of us can change the wrongs of the past but we can commit, with all our hearts, to learning its lessons and to finding creative ways to right inequalities that endure.”
It was a carefully crafted speech, with no direct mentions of “slavery” or “reparations”.
For many Caribbean and African countries, his words won’t have gone far enough.
They are seeking a formal apology from countries involved in slavery.
Eric Phillips, a leading campaigner from Caricom, the body representing Caribbean countries, said: “No reparations, no trade, should be the new motto of countries that seek reparations.”
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He described Sir Kier Starmer’s decision not to back reparations as “cruel” and questioned the future of the Commonwealth.
“I just don’t understand the relevance of the Commonwealth if Prime Minister Starmer takes this cruel approach,” he said.
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The King is caught in the middle. Buckingham Palace says he sits above politics and cannot comment or apologise without his government’s agreement.
But the royal family were historically one of the biggest traders of enslaved people. Not only that, it was a trade they made huge profits from.
The King has previously spoken of his “personal sorrow” about slavery, and commissioned research to “deepen” his understanding into his family’s historic links to the slave trade.
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But, for many, his acknowledgement and response so far aren’t enough. It is a fractured issue causing continuing tension and trouble within the Commonwealth, both of which threaten its very future.
The King ended optimistically: “Let us learn from the lessons of the past. Let us be proud of who we are today. And, together, let us forge a future of harmony.”
It was a speech that made the most of its moment, but many will say it was a missed opportunity.