Dukes in the United Kingdom
Duke, in the United Kingdom, is the highest-ranking hereditary title in all four peerages of the British Isles. A duke thus outranks all other holders of titles of nobility (marquess, earl, viscount and baron).
Baron Rivers
Baron Rivers was a title that was created four times in British history, twice in the Peerage of England, once in the Peerage of Great Britain and once in the Peerage of the United Kingdom.