When someone of a royal family is born, the name they are given has already been vetted many times over. But if they eventually become the monarch, they can decide to take a different name. How common or simple that is depends on the country. But keeping up with monarchs and their names over thousands of years can be daunting.
Pop quiz, hotshot. The last King of England who went by the name of Edward was Edward VIII (1936). So, how many King Edwards has England had?
That came about because early kings of Britain were called by some sort of modifier: Edward the Elder, Edward the Martyr, Edward the Confessor… you get the idea. When they ran out of descriptive terms, they started using numbers. But there are cases of royalty elsewhere where the numbers get skipped, which will cause future historians no small amount of anguish, especially when the digital records crash. Read about some of the weird things that happen when we try to keep track of monarchs using common family names at NewStatesman. -via Metafilter