In France, some important "seigneuries" (lordships) were styled principalities since the late Middle Ages. Their lords had no specific rank, and were always officially subordinate to dukes and to foreign princes. Beginning in the late sixteenth century, some of France's leading families, denied the "rank" of prince at court, assumed the "title" of prince. Often it was claimed on behalf of their eldest sons, subtly reminding the court that the princely title was subordinate — at least in the law — to that of duke-peer, while minimising the risk that the princely style, used as a mere courtesy title, would be challenged or forbidden. Typical were the ducs de La Rochefoucauld: Their claim to descend from the independent duke Guillaume IV of Guyenne, and their inter-marriages with the sovereign dukes of Mirandola, failed to secure for them royal recognition as foreign princes. Yet the ducal heir is still known as the "prince de Marcillac", although no such principality ever existed, within or without France.