Dampierre

The House of Dampierre was a noble family named after its lordship in Champagne, whose earliest known ancestor Guy I held its castle in the twelfth century. It rose through marriage: William II of Dampierre wed Margaret II, Countess of Flanders. In the long succession war against the House of Avesnes, Louis IX arbitrated in 1246, awarding Flanders to Margaret's Dampierre children and Hainaut to the Avesnes; defeat at West-Capelle in 1253 forced the family to accept the division.

Guy of Dampierre ruled as Count of Flanders, while a younger son founded the line that held Namur. Marriage added Nevers in 1280 and Rethel in 1328; by 1337 the family held Flanders, Nevers, Rethel and Namur, and Blanche of Namur was queen of Norway and Sweden.

The senior line ended with Countess Margaret III in 1405, when Flanders, Artois, Nevers and Franche-Comte passed to her son John the Fearless as the core of the Valois-Burgundy dominions. The Namur line died out in 1429.