How did Philip II Augustus escape the influence of his uncles from the house of Champagne?

To escape the influence of his uncles from the house of Champagne—Henry I, Guillaume, and Thibaut V—who sought to control him, Philip II Augustus took decisive political action. On April 28, 1180, he married Isabella of Hainaut, the niece of Philip of Alsace, the count of Flanders. This marriage secured him the territory of Artois as a dowry and created a new political alliance that countered his uncles' influence.1

Furthermore, when Henry II of England arrived in Normandy, potentially to support the house of Champagne, Philip II preemptively negotiated with him. At Gisors on June 28, 1180, Philip renewed an agreement previously made by his father, Louis VII. This diplomatic maneuver effectively isolated the house of Champagne, allowing Philip II to make independent decisions and consolidate his authority before his father’s death later that year.1