Late son of Louis VII and his third wife Adele of Champagne, Philip Augustus became king of France in 1180, before his fifteenth year. He then set about asserting his power by expanding his kingdom.
His strategy was the following: he exploited, in a subtle way, the dissensions between the king of England and his four sons (including Richard the Lionheart and John Lackland). It was a real double game opposing first the sons and the father, then the brothers between them.
In 1191, Philip Augustus took advantage of Richard the Lionheart's crusade to form an alliance with his younger brother John Lackland. The latter ceded Normandy and other territories to him. On his return from the Holy Land, Richard was taken prisoner by the new Germanic emperor. Released after fourteen months of detention, he resumed the war against his rival Philip Augustus. He died in 1199 and was succeeded by his brother John Lackland.
After the capture of Château-Gaillard, Philip Augustus set out to conquer the Touraine region so dear to the Plantagenets. In 1205, Philip Augustus took the fortresses of Loches and Chinon (after a nine-month siege). In Chinon, he signed a five-year truce with John, who gave up all his possessions north of the Loire. But it was the victory of Bouvines which, in 1214, definitively established the victory of the Capetians over the Plantagenets.
By the time of his death, the royal estate had tripled in size and covered a third of France. Philip Augustus remains famous for having structured the administration of the kingdom. He also demonstrated innovation and rationalization in architecture by building a large number of castles and circular towers, such as the Fortress of Chinon with the Coudray Tower.