Margaret, in 1345, succeeded following the death in Friesland of her brother William II. In 1345, she granted "to foreigners, of whichever countries they might be, the faculty to enjoy the same rights as residents of Le Quesnoy provided that they fix their residence in the town". She married Louis IV, Holy Roman Emperor became a widow of her husband in 1347: when she moved to Le Quesnoy where she stayed until the end of her life, and made the castle her preferred home. The cloth industry flourished there at that time: indeed, when the cloth industry of Mons was reorganized in 1352 it called upon clothmaking specialists of Le Quesnoy and a fuller was even called to settle in Mons with his working material.