The title of prince of the Holy Roman Empire was conferred in 1704 upon all the children heirs and lawful descendants, male and female, of John Churchill, the first duke of Marlborough. The title of prince of Mindelheim was granted in 1705 to all male descendants and daughters of the first duke. But following the Treaty of Utrecht in 1713 and the Treaty of Rastatt in 1714 the principality passed to Bavaria. The right of the dukes of Marlborough to use the style and title was thus lost, and any residual rights would have expired in 1722 on the death of the duke, as they could not pass to a daughter (unlike his British titles). Despite this it is still common practice to describe the Duke of Marlborough as a Prince of the Holy Roman Empire and Prince of Mindelheim. This paper considers the differences in the treatment of the descent of the British and imperial titles.