Probably Prince Harry, Duke of Gloucester, 1900-1974. He was a Henry who was called Harry too. Prince William b.1982 was named after Prince William of Gloucester (1942-72), a close friend of Prince Charles. It's probable that Harry was named after the other Harry who also died ten years earlier. Or they just like the name.
According to Yvonne:
His father the Prince of Wales explained that "the name [William] had been chosen because he had no close relatives of that name."
The rest, I can make an educated guess at: Arthur is a fairly traditional English and British royal name; Philip is his grandfather The Duke of Edinburgh; Louis was Philip's uncle Lord Mountbatten of Burma. He also could have been named after King William Orange
He is named after many people
1. George is a name that come Phillips grandfather who was King George of Greece. It is also a middle name of Phillip, Charles and William
2. Alexander comes from a few places as well. Phillip is a descendant of Alexander II of Russia and Philip had a cousin who was King of Greece for a short while named Alexander. There is speculation it is also for the Queen as well since one of her middle names is Alexandra
3. Louis is one of Williams middle names and is probably a nod to Philllips uncle Louis Mountbatten who helped Elizabeth and Phillip meet and whose death brought Diana and Charles together.
Prince William's family name is 'Mountbatten-Windsor'.
Queen Elizabeth runs the Royal House of Windsor, and Windsor is the family's (including Prince William's) last name.
Queen Elizabeth and Prince William
The Royal family name is Windsor.
The Queen, Prince William, Princess Beatrice, The Duchess Of Cambridge and Prince Charles
William and Catherine (Kate) are the Williams family now or if you mean queen Elizabeth's family it is called Windsor
Prince Williams father, Prince Charles, is know as the Prince of Wales. He is to. Therefore, he is William of Wales. To learn more about the present royal family,
The House of Windsor came into being in 1917, when the name was adopted as the British Royal Family's official name by a proclamation of King George V, replacing the historic name of Saxe-Coburg-Gotha. It remains the family name of the current Royal Family. Prince Charles, his son Prince William and Prince William's new son are all members of the House of Windsor. There is no such thing as the "House of Mountbatten". One of Prince Charles's relatives was Lord Louis Mountbatten, which was a courtesy tile. His family name was Battenburg.
Prince Harry
Gordon Prince's birth name is William Gordon Prince.
Because he is the son of the HRH the Prince of Wales he uses the name Prince William of Wales.
Prince Williams' family name is Mountbatten-Windsor however the Royal Family don't tend to use surnames unless the situation requires it, in which case, the surname will be allocated depending on the person's title and status. Depending on the situation, the surnames 'Wales' or 'Cambridge' could also be (and have been) used by the Prince
His full name is William Arthur Philip Louis.His official title is Prince William of Wales.