By his divorce from Isabella of Gloucester he offended the English baronage (1200); by his marriage with Isabella of Angouleme, the betrothed of Hugh of Lusignan, he gave an opportunity to the discontented Poitevins for invoking French assistance and to Philip Augustus for pronouncing against him a sentence of forfeiture.
He therefore set himself up in rivalry with John Lackland, youngest son of Henry II., and supported by Philip Augustus of France, and aided by William des Roches, seneschal of Anjou, he managed to enter Angers (18th of April 1199) and there have himself recognized as count of the three countships of Anjou, Maine and Touraine, for which he did homage to the king of France.
Capturing Rochester castle, John met with some other successes, and the disheartened barons invited Louis, son of Philip Augustus of France and afterwards king as Louis VIII., to take the English crown.
Not being permitted to succeed Longchamp as the head of the administration, John next turned to Philip Augustus for help. A bargain was struck; and when Richard was captured by Leopold, duke of Austria (December 1192), the allies endeavoured to prevent his release, and planned a partition of his dominions.
Confirming what was doubtless an older custom, Philip Augustus decreed the quarantaine-le-roi, which suspended every act of reprisal for at least forty days; and in 1257 Louis IX.
Finally the birth of Philip Augustus (1165), after thirty years of childless wedlock, saved the kingdom from a war of succession just at the time when the powerful Angevin sway, based entirely upon force, was jeopardized by the rebellion of Henry II.s sons against their father.
While John, after two inroads, turned back to his Guienne possessions on the 3rd of July, it was not until three weeks later that the emperor concentrated his forces at Valenciennes, and in the interval Philip Augustus had countermarched northward and concentrated an army at Peronne.
Of England espoused the cause of Guy, who came from his own county of Poitou, Philip Augustus espoused that of Conrad.
Henry once declined an offer of the Empire, made by the opponents of Frederick Barbarossa; and he steadily supported the young Philip Augustus against the intrigues of French feudatories.
And Henry II., the itinerant baillis of Philip Augustus king of France, or the royal enqueteurs of St Louis originated from this source.