County of Vermandois

Vermandois was a traditional French county in Picardy, appearing during the Merovingian period. Its name derives from the ancient tribe, the Viromandui. In the 10th century, it was organized around the castellan domains of St Quentin and Péronne. Pepin I of Vermandois, a descendant of Charlemagne, was an early hereditary count. His grandson, Herbert II, significantly increased the house's territorial power and imprisoned King Charles the Simple. Later, Herbert IV received the county of Valois through marriage. The county eventually passed to his sister Adela, who married Hugh the Great, a leader of the First Crusade. Their son, Raoul I, married Petronilla of Aquitaine.