They are titles created and bestowed on legitimate sons and male-line grandsons of the British monarch, usually upon reaching their majority or marriage.
[2][3] This decree accorded precedence to any peer related by blood to the sovereign above all others of the same degree within the peerage.
The order did not apply within Parliament, nor did it grant precedence above the archbishop of Canterbury or other Great Officers of State such as is now enjoyed by royal dukes.
It did not matter how distantly related to the monarch the peers might be (presumably they ranked among each other in order of succession to the Crown).
Similarly, upon the death of Prince Arthur, Duke of Connaught and Strathearn (1850–1942) (the third son of Queen Victoria), his only male-line grandson, Alastair, Earl of Macduff (1914–43), briefly succeeded to his peerages and was styled His Grace.
The situation is similar in the Channel Islands, where the monarch is addressed as Duke of Normandy, but only in accordance with tradition.
The Act provides that a successor of a person thus deprived of a peerage can petition the Crown for revival of the title.
Includes dukes of: Albany, Albemarle, Bedford, Cambridge, Clarence, Connaught and Strathearn, Cumberland, Edinburgh, Gloucester, Gloucester and Edinburgh, Hereford, Kent, Kintyre and Lorne, Norfolk, Ross, Somerset, Sussex, Windsor, and York, but only when royally.