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.
List of earls in the peerages of Britain and Ireland
This is a list of the 193 present and extant earls in the Peerages of the England, Scotland, Great Britain, Ireland, and the United Kingdom. Note that it does not include extant earldoms which have become merged (either through marriage or elevation) with marquessates or dukedoms and are today only seen as subsidiary titles. For a more complete list, which adds these "hidden" earldoms as well as extinct, dormant, abeyant, and forfeit ones, see List of earldoms.