Bourchard and Margaret continued as a married couple, having 3 children, as their conflict with Joan grew violent and Bouchard was captured and imprisoned in 1219.

While he was in Rome, Joan convinced Margaret to remarry, this time to William II of Dampierre, a nobleman from Champagne.

The disputes regarding the validity of the two marriages and the legitimacy of her children by each husband continued for decades, becoming entangled in the politics of the Holy Roman Empire and resulting in the long War of the Succession of Flanders and Hainault.

The eldest son, John I of Avesnes, who was uneasy about his rights, convinced William of Holland, the German king recognized by the pro-papal forces, to seize Hainaut and the parts of Flanders which were within the bounds of the empire.

Charles took up her cause and warred with John I of Avesnes, but failed to take Valenciennes and just missed being killed in a skirmish.