Duke of Cleveland is a title that has been created twice, once in the Peerage of England and once in the Peerage of the United Kingdom. The dukedoms were named after Cleveland in northern England. The first creation in 1670 (along with the barony of Nonsuch and the earldom of Southampton) was for Barbara Castlemaine, a mistress of King Charles II. The dukedom was created with a special remainder allowing it to be inherited by her first son, Charles FitzRoy, and his heirs male, then by her third son, George FitzRoy, 1st Duke of Northumberland, both being her illegitimate sons by Charles II. Charles FitzRoy was created Duke of Southampton in 1675 and inherited the dukedom of Cleveland in 1709.