King Charles gave his younger brother Prince Edward a new prominent position after Prince William represented his father according to a long-standing royal norm.
According to Buckingham Palace, Duchess Sophie's husband took on the great role of representing the Royal Family as the world watched Pope Leo XIV's inauguration in Vatican City.
Prince Edward, the Duke of Edinburgh, 61, who has become close to King Charles after the death of his mother, the late Queen Elizabeth II, attended the event in Rome on Sunday instead of King Charles or the Prince of Wales.
Earlier, a Buckingham Palace official announced that "The Duke of Edinburgh will represent His Majesty at the inauguration of Pope Leo XIV."
No explanation has been provided for King Charles' absence from the celebration held in St. Peter's Square on Sunday, May 18.
Duchess Sophie, the Duchess of Edinburgh, did not accompany Prince Edward to witness the installation of the first North American Pope.
Last month, Prince William represented King Charles and the royal family for Pope Francis' burial at the Vatican.
William attended the ceremony "on behalf" of King Charles III, in accordance with current custom.