Claim: Charles Fitzroy received the subsidiary titles of Earl of Chichester and Baron Newbury, then upon his mother's death in 1709, the 1st Duke of Southampton succeeded to her hereditary peerages.
Evidence: Duke of Southampton was a title in the Peerage of England. It was created in 1675 for Charles FitzRoy, an illegitimate son of King Charles II by his mistress, the 1st Duchess of Cleveland. Together with the dukedom, Charles Fitzroy also received the subsidiary titles of Earl of Chichester and Baron Newbury. Upon his mother's death in 1709, the 1st Duke of Southampton succeeded to her hereditary peerages (the dukedom of Cleveland, earldom of Southampton and barony of Nonsuch).