Edward’s presence signals both his growing importance in his own family, as well as the monarchy's importance to British diplomacy at a potentially rocky moment.

The Duke of Edinburgh, 60, sat next to Canadian Prime Minister Justin Trudeau inside the Washington National Cathedral. He is the only royal in attendance at the state funeral today. It's as yet unclear if he will carry out any other engagements while in the United States.

On Jan. 9, the Duke of Edinburgh, 60, stepped out in the U.S. capital city to pay respects to the nation’s 39th president, who died on Dec. 29 at 100 years old. Prince Edward sat beside Prime Minister Justin Trudeau of Canada, a Commonwealth country and crown realm, for the solemn service.