The titles can be inherited, but cease to be called “royal” once they pass beyond the grandsons of a monarch.
As with any British peerage, once this title becomes extinct it can be recreated by the reigning monarch.
During her reign, the Queen extended the style of the Royal Highness name from the eldest living legitimate son of the eldest legitimate son of a Prince of Wales to all the children of the eldest son of a Prince of Wales should have and enjoy the style, title and attribute of Royal Highness.
In addition to the three dukedoms the Queen has created, there are still three principal titles and two secondary titles including Prince Philip Duke of Edinburgh, the Duke of Gloucester, the Duke of Kent, Prince Charles Duke of Cornwall and the Duke of Rothesay.
