The Dampierre family played an important role during the Middle Ages. They were Count of Flanders and later also Count of Nevers, Rethel, Artois and Franche-Comté. The senior line of the House died out with Margaret III. She was succeeded in Flanders, Artois, Nevers and Franche-Comté by her eldest son John the Fearless and in Rethel by her younger son Anthony, which marked the start of the House of Valois-Burgundy. The junior line, springing from a younger son of Guy I reigning in Namur, ended in 1429. The members of House of Dampierre had an antagonistic relation with the House of Avesnes.