KIGALI, Rwanda (AFP) — Prince Charles told Commonwealth leaders Friday that the choice to become a republic or abandon the queen as head of state was theirs alone, and expressed “personal sorrow” at Britain’s legacy of slavery.

The British heir to the throne addressed the opening of a Commonwealth Heads of Government Meeting (CHOGM) in Rwanda as the host nation faced scrutiny over its rights record and a much-criticised migrant deal with the UK.

Charles is representing Queen Elizabeth II as the 54-nation grouping of mostly former British colonies grapples with questions over its future relevance and modern profile.

Republican movements are taking root in a number of Commonwealth nations and some are seeking reparations for colonial-era injustices like slavery.

Charles acknowledged the change underfoot and said the Commonwealth — which represents one-third of humanity — would always be “a free association of independent, self-governing nations”.

“The Commonwealth contains within it countries that have had constitutional relationships with my family, some that continue to do so, and increasingly those that have had none,” he told an audience of presidents and prime ministers.

“I want to say clearly, as I have said before, that each member’s constitutional arrangement, as republic or monarchy, is purely a matter for each member country to decide.”

He also acknowledged that the roots of the Commonwealth — which includes as members nations from Europe to Africa, Asia and the Americas — “run deep into the most painful period of our history”.

“I cannot describe the depths of my personal sorrow at the suffering of so many, as I continue to deepen my own understanding of slavery’s enduring impact,” he said.