Mountbatten-Windsor
Mountbatten-Windsor is the surname available to descendants of Queen Elizabeth II and Prince Philip, Duke of Edinburgh and can be used by them whenever a surname is required. Generally, those that are entitled to, and use, the royal style HRH Prince or Princess have no need of a surname. An example of when a surname is needed is when they get married. Mountbatten-Windsor combines the British royal family's House name of Windsor and Prince Philip's adopted surname of Mountbatten. Its use was authorised by a 1960 Privy Council declaration.