He knew the foibles of the romantic and picturesque Richard; and he also knew that John, corrupt to the core, was a traitor to whom no trust would be sacred.

In his own cold-blooded fashion he intended to use them both.
John had conspired against his own father, now Philip would help him to supplant his brother, while Richard was safely occupied in Palestine.
And when he had made John king, he, Philip Augustus, was to be rewarded by the gift of Normandy! With this in view, Philip returned to France.
It was an ingenious plot, but all was spoiled by Richard's safe return from the thrilling adventures of the Crusade.

In 1199, however, the crown passed naturally to John by the death of his brother, and this vicious son of Eleanor was King of England.
There were other means of recovering his lost possessions.

Philip espoused the cause of the young Arthur, John's nephew, a rival claimant to the English throne.

And when that ill-fated Prince was murdered, as is believed by the orders of his uncle, for this and other offences King John, as Duke of Normandy--thence vassal to the King of France--was summoned to be tried by his peers.
When after oft-repeated summons John refused to appear at Philip's court, by feudal law the King of France had legal authority to take possession of the dukedom.
In vain did King John strive to defend by arms his vanishing possessions.