Four years ago today, Prince Louis Arthur Charles was born, and as ever, the Cambridge couple gave us a lovely look at his birthday celebration with some tantalizing beach snaps taken by his mother, the Duchess of Cambridge.

Louis' name was publicly announced four days after his birth on April 27, 2018, and it is one of three middle names of Louis' father, Prince William, Prince Charles' mentor, Louis, who died unceremoniously in an IRA bombing in 1979, three years before William's birth It is believed to have been given in honor of Sir Louis Mountbatten, Prince Charles' mentor and the man who died in an IRA bombing in 1979, three years before William was born. Prince Louis' brother Prince George also shares this name and uses it as one of his two middle names.

As for Prince Louis' official title (His Royal Highness Prince Louis of Cambridge), according to the Mirror, this is only possible because of steps taken by the Queen to override the rules established by King George V before Prince Louis was born.

"In 1917, George V laid down new guidelines as to which royalty should be given titles and who was too low in the line of succession to be entitled to them. He decided that all of the monarch's children would automatically become princes or princesses, and that grandchildren born in the male line would likewise become princes or princesses." Great-grandchildren, however, were not included in that list."

Times were different then, and there was no provision for great-grandchildren. As with the Queen, the monarch did not usually live to be 96 years old, so it was probably thought that provision for great-grandchildren was not necessary. The "problem" Before George was born, despite being the future king, under the current rules he was the great-grandson of the monarch, not his grandson, and therefore had no title at all.

"The Queen intervened and said George would get the title, and decided to extend the change to all of Kate and William's children," the Mirror reported, putting all Cambridge children on the same footing.

However, children born to Prince Harry and other royal grandchildren (such as Princess Eugenie and Princess Beatrice) were not covered by this provision. In other words, once Prince Charles ascended to the throne, all of the monarch's grandchildren, i.e., the three Cambridge children and Harry's children Archie and Lili, would all automatically be entitled to be named His Highness or Her Royal Highness. It remains to be seen whether Archie and Lili will make use of these titles.