Edward III of England, Margaret's brother-in-law through her sister Philippa of Hainault, came to her aid, winning a naval engagement off Veere in 1351; a few weeks later the Hooks and their English allies were defeated by William and the Cods at Vlaardingen, an overthrow which ruined Margaret's cause. Edward III shortly afterwards changed sides, and the empress saw herself compelled (1354) to come to an understanding with her son, he being recognized as count of Holland and Zeeland, she of Hainaut. Margaret died two years later, leaving William in possession of the entire Holland-Hainaut inheritance (July 1356). William was married to Matilda ("Maud" in the English style) of Lancaster, sister to Blanche of Lancaster.