King Charles on Tuesday thanked Sinn Fein's leader in Northern Ireland for her "incredibly kind words" about his mother Queen Elizabeth, the latest sign of warmth between the former political wing of the Irish Republican Army and the crown.
Michelle O'Neill issued a statement following the Queen's death last week saying she was "grateful for Queen Elizabeth's significant contribution and determined efforts to advancing peace and reconciliation" and that she "led by example."
O'Neill has since said she was looking forward to working with Charles, and several other senior members of Sinn Fein have offered their sympathies.
The IRA, which ended its 30-year armed campaign against British rule in Northern Ireland after a 1998 peace deal, killed Charles' great uncle, Louis Mountbatten, in a 1979 bomb attack.
Charles was also ceremonial head of the British Army's Parachute Regiment, members of which killed 13 Roman Catholic civil rights marchers in the 1972 Bloody Sunday shootings.
But relations between Sinn Fein and the British royals were transformed by a 2012 handshake between Elizabeth and then Deputy First Minister of Northern Ireland Martin McGuinness, a former IRA commander, in Belfast
During his first visit to Northern Ireland as King on Tuesday, Charles warmly shook O'Neill's hand and said "Thank you so much for the incredibly kind things you said about my mother."
"She played a great role here in terms of reconciliation... It's the end of an era for sure," O'Neill replied.
"It is," said the King. "What is it they say: you can never read your obituaries and all the nice things people say about you. Always very frustrating."
Charles also shook hands with senior Sinn Fein member Alex Maskey, the acting speaker of the Northern Ireland Assembly. In a speech, Maskey said the Queen had personally demonstrated how to break down barriers and encourage reconciliation.
(Reporting by Conor Humphries and Padraic Halpin, Editing by Alexandra Hudson)