The king paid tribute to the “courage, resilience and solidarity” of those who took part in the historic invasion of Normandy, a turning point in the fight against Nazi Germany.

“It is our duty to ensure that we and future generations do not forget their service and their sacrifice in replacing tyranny with freedom,” Charles told the crowd in his address.

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Queen Camilla, who joined him at the event on Southsea Common in Portsmouth, could be seen in tears as a veteran recounted his memories of the invasion. Charles also appeared to wipe a tear from his eye at one point.

The king and queen joined other heads of state and world leaders in Normandy on Thursday to mark the day of the landings. They were in Ver-sur-Mer for the U.K. commemorative event at the British Normandy Memorial, along with Prime Minister Rishi Sunak, opposition Labour Party leader Sir Keir Starmer and French President Emmanuel Macron.

William was set to give a speech at the Canadian event at Juno Beach, before joining veterans and heads of state for the official international ceremony on Omaha Beach.

Both Charles and Kate have declined to specify what type of cancer they have or details about their prognosis, although the 75-year-old monarch has attended several engagements since he resumed public duties earlier this year.

It remains unclear when Kate will return to public duties, after revealing her diagnosis in the wake of fervent speculation about her whereabouts following what the palace said was planned abdominal surgery.