Royal dukedoms in the United Kingdom
In the British peerage, a royal duke is a member of the British royal family, entitled to the titular dignity of prince and the style of "His Royal Highness" who holds a dukedom. Dukedoms are the highest titles in the British roll of peerage and the holders of these particular dukedoms are Princes of the Blood Royal. The holders of the dukedoms are royal not the titles themselves. They are titles created and bestowed on legitimate sons and male-line grandsons of the British monarch, usually upon reaching their majority or marriage. The titles can be inherited but cease to be called "royal" once they pass beyond the grandsons of a monarch. As with any peerage, once the title becomes extinct, it may subsequently be recreated by the reigning monarch at any time.
Order of precedence in England and Wales
Peers and their families make up a large part of these tables. It is possible for a peer to hold more than one title of nobility, and these may belong to different ranks and peerages. A peer derives his precedence from his highest-ranking title; peeresses derive their precedence in the same way, whether they hold their highest-ranking title in their own right or by marriage. The ranks in the tables refer to peers rather than titles: if exceptions are named for a rank, these do not include peers of a higher rank (or any peers at all, in the case of baronets). No exceptions are named for most categories, owing to their large size.