The former Prince Andrew was said to be his mother’s favourite child and was once a poster child of the royal family.
But now his association with convicted sex offender Jeffrey Epstein, and renewed sexual abuse allegations in the posthumous memoir of one of Epstein's victims, Virginia Roberts Giuffre, have led to one of the most dramatic falls from grace in modern royal history.
Andrew is being stripped of all his royal titles, styles and honours, by order of his brother, King Charles.
The titles he has lost include Prince, His Royal Highness, The Duke of York, Earl of Inverness, and Baron Killyleagh. He's also been stripped of his honours, including the Order of the Garter and his status as a Knight Grand Cross of the Victorian Order.
He continues to deny the allegations against him. But from now on he will be known simply as Andrew Mountbatten Windsor.
So where does that surname come from?
Why royals often do not use a surname
It's a common question posed by members of the public. Do members of the royal family have a surname, and what is it if they do?
You might remember when Meghan Markle insisted on her Netflix cooking show that her surname is Sussex.
As the royal family's official website explains, the British royal family can be known by the name of their royal house and by a surname, which is not always the same.
Just like normal people often take their father's surname, sovereigns too normally take the name of their "house" from their father.
They quite often don't use a surname at all, and before World War I were only known by the name of the house or dynasty they belonged to — the House of Saxe-Coburg and Gotha.
A radical change occurred in 1917 when George V (the late Queen Elizabeth II's grandfather) adopted Windsor as the name of the "house" as well as the surname of his family.
The change was made because "Saxe-Coburg Gotha" was deemed to sound too German.
According to the royal family website: "The family name was changed as a result of anti-German feeling during the First World War, and the name Windsor was adopted after the castle of the same name."
But in common usage, kings and queens use their first name only.
Where did the name Mountbatten-Windsor come from?
Mountbatten-Windsor is a combination of Windsor, the surname of Andrew's mother Queen Elizabeth II, and Mountbatten, the adopted surname of her husband, Andrew's father, Prince Philip.
It first appeared on an official document in 1973 when Princess Anne used it as her surname on the marriage certificate recording her union with her first husband, Captain Mark Phillips.
Queen Elizabeth had started using the surname Windsor, borrowed from the name of the royal estate just outside London, in 1952.
The then princess Elizabeth had married former Greek and Danish prince Philip Mountbatten in 1947.
In 1960, the couple decided they wanted their own direct descendants to be distinguished from the rest of the royal family, and so they would carry the hyphenated last name Mountbatten-Windsor.
But there were exceptions: any royal who is entitled to call themselves a prince or a princess, or His/Her Royal Highness, doesn't use the surname.
So, on the occasions that the late queen's children need surnames, that surname is Mountbatten-Windsor.
It is unclear why Andrew Mountbatten Windsor is not hyphenated in the Buckingham Palace statement announcing the revoking of his royal privileges.
Mr Mountbatten Windsor's children with ex-wife Sarah Ferguson — the princesses Beatrice and Eugenie — will keep their titles.
But hang on, the royals don't always use the Mountbatten-Windsor name
You might remember that when Prince William and Prince Harry served in the military, they went by William Wales and Harry Wales.
That was because their father was the Prince of Wales.
At the same time, when Prince Harry's son made his public debut, it was announced his name was Archie Harrison Mountbatten-Windsor.
Upon the accession of King Charles, Archie and his little sister Lilibet became prince and princess because Prince Harry is the son of a monarch, despite not being a working royal.
Tell me about Mountbatten, specifically
Mountbatten is an adopted name taken from the original Battenberg and was changed during World War I to distance the family from such a Germanic-sounding name.
Prince Philip had significant German ancestry on both sides of his family.
But from 1914 — 1918, Britain and its allies were at war with Germany.
So, when George V changed the name of the British royal house from the German house of Saxe-Coburg and Gotha to the house of Windsor, his British relatives with German names followed suit.
This included the elder Mountbatten.
King Charles's great-uncle Louis Mountbatten, Queen Elizabeth's cousin, and the last viceroy of British-ruled India, was killed by IRA paramilitaries in 1979.
Prince Philip was related to his wife, Queen Elizabeth II, through both maternal and paternal lines.
