When members of the British Royal Family travel abroad, they must follow an important rule that was established after an incident in 1952 involving the newly ascended Queen Elizabeth II.
At that time, the new Queen was unprepared when her father, King George VI, suddenly died while she was overseas.
The rule put in place following this aims to prevent a similar situation from occurring in the future.
The Black Mourning Suit: The Crucial Royal Rule for Traveling Abroad
In February 1952, Princess Elizabeth was in Kenya at the beginning of a Commonwealth tour when she learned that her father, King George VI, had passed away unexpectedly back in England.
As his death was sudden and Elizabeth had not anticipated needing to mourn while abroad, she had not packed a black dress in her luggage.
When her plane landed back in England the next day, an appropriate mourning dress had to be quickly brought on board for her to change into before disembarking.
To avoid this kind of situation in the future, it became standard protocol for all senior members of the Royal Family to pack a black mourning outfit whenever traveling overseas.
This preparation ensures that they will be properly dressed to convey the necessary grief and respect should another royal or dignitary pass away while they are abroad.
The black ensemble is seen as essential in formally communicating the demise of a figure and the shift in succession that may follow.
This rule has been closely followed throughout the subsequent decades up to the present day. When, King Charles, Prince William, or other royals take official trips abroad, a black mourning dress or similar garment is always discreetly included in their luggage.