The foundling - Georgette Heyer

It was undoubtedly better to be the Seventh Duke of Sale than a sweep`s apprentice, but he was much inclined to think that to have been plain Mr Dash of Nowhere in Particular, would have been preferable to either of his callings. The shy, young Duke of Sale has never known his parents. Instead his Grace Adolphus Gillespie Vernon Ware(Gilly for short) has endured twenty-four years of rigorous mollycoddling from his uncle and valet. But his natural diffidence conceals a rebellious spirit. So when Gilly hears of Belinda, the beautiful foundling who appears to be blackmailing his cousin, he has no sooner entered his new and dangerous world than he is plunged into a frenzy of intrigue, kidnap and adventure.