The House of Vermandois was a noble family in medieval France, originating from the region of Vermandois. It was established in the 9th century and played a significant role in the feudal system, with members often holding important titles and lands. The family is known for its connections to the Capetian dynasty, which ruled France for centuries. Members of the House of Vermandois were influential in various historical events, including the Crusades. They often intermarried with other noble families, strengthening their political alliances. The house eventually declined in power, but its legacy remains significant in the history of French nobility.