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).
Canadian peers and baronets
In 1891, Lord Mount Stephen became the first Canadian to be elevated to the Peerage of the United Kingdom. The significant losses of the First World War included many direct heirs to titles and some replacements were found in Canada resulting in the acquisition of titles by Canadians who, as British subjects, were eligible to inherit.