Princes of Wales
This one is a bit tricky to understand, especially if you are not from the UK or any other commonwealth country. So Prince Charles, who is now King Charles, was always known as the Prince of Wales, but now that he is king, that title is lost. Prince William now holds the title of Prince of Wales in his place.
The lucky William will also be receiving the former Prince’s Duchy of Cornwall. Since Charles now took the head and became King, the old titles are all passed on down the line. It’s a very old system with strict rules that have not been changed for quite some time, and for good reason.