Medieval county and duchy, northern France.
It corresponds to the southeastern quarter of the modern département of Oise, with an adjacent portion of Aisne. It was under the Merovingian kings ( 0441; 500751) and their successors, the Carolingians, until it became a hereditary countship. In 1214 King Philip II Augustus annexed it to the royal domain. The duchy's last representative, Henry III, was succeeded in 1589 by the house of Bourbon . In 1790 it was abolished in the redivision of France into département s.