How did Isabella of Hainaut’s dowry help Philip II Augustus expand the French royal domain?

Isabella of Hainaut’s dowry was instrumental in helping Philip II Augustus expand the French royal domain by providing him with the territory of Artois.1

Philip married Isabella in 1180, shortly after his coronation, specifically to escape the political tutelage of his uncles from the house of Champagne. The territory of Artois, promised as part of her dowry by her uncle, Philip of Alsace (the count of Flanders), allowed the king to extend royal authority toward the northern border of Flanders. While the acquisition began with this marriage, the territory was fully secured under royal control by 1212. This expansion served as a key step in Philip's broader efforts to consolidate the realm and strengthen the French monarchy.12