In 1199, Richard the Lion Heart died after being shot by a cook outside the castle of Chalus in the Limousin. The Empire was split between supporters of Arthur and supporters of John. Philip was for himself, with a bit for Arthur. That year was one of John's best years, where he showed that he could be effective.
The Death of Richard the Lion Heart
The legend is that Richard went to Chalus in the Limousin because a treasure trove had been found, the local lord refused to hand it over, and Richard was going down there to get his hands on it. It's much more likely that in fact this was part of a wider campaign against the rebellious Count of Angouleme and Viscount of Limoges.
Whatever the reason, Richard was on the verge of takin the castle when he went for a wander round hte castle, without armour but with a shield carried by a man at arms. On the tower was a lone man with a crossbow, using a frying pan as a shield. He shot towards Richard who applauded the shor - and so ducked too late. He was hit between neck and shoulder. back in his tent, Richard couldn't pull the whole thing out so a surgeon was called, who made even more of a mess of it. 3 days later Richard was dead.
The accession of John
Public opinion was split - Arthur, the son of Geoffrey of Brittany or John, son of the old king? England and Normany declared for John; Maine Anjou and Touraine for Arthur. Aquitaine wasn't a problem - it belonged to Eleanor. John was decisive. He talked round the key nobleman of greater Anjou, William des Roches. His defection too all the wind out of Arthur's sails. John took the fealty of 15 counts - including the crucial allies, the Counts of Flanders and Boulogne. Phillip had attacked eastern Normandy and Evreux, but now realised he could make little headway - and agreed to a truce.