The title of Duke of Grafton was created in 1675 by Charles II of England for his 2nd illegitimate son by the Duchess of Cleveland, Henry FitzRoy. The most famous duke was probably Augustus Henry FitzRoy, 3rd Duke of Grafton, who served as Prime Minister in the 1760s. The Duke of Grafton holds three subsidiary titles, all created in 1672 in the peerage of England: Earl of Euston, Viscount Ipswich, and Baron Sudbury. Wikipedia
The definitive Wikipedia entry for Duke Of Grafton. Wikipedia is the biggest multilingual free-content encyclopedia on the Internet. en.wikipedia.org/wiki/Duke_of_Grafton
The sons and daughters of the Dukes of Grafton and the daughters of the Earls of Euston bear the courtesy titles of Lord/Lady X Fitzroy, unless and until they acquired some higher title. pages.prodigy.net/ptheroff/gotha/grafton.html
