John detected this correspondence; and to prevent the dangerous effects of it, he sent forces into Normandy, the chief seat of the king of Navarre's power, and attacked his castles and fortresses.

But hearing that Edward had prepared an army to support his ally, he had the weakness to propose an accommodation with Charles, and even to give this traitorous subject the sum of a hundred thousand crowns, as the purchase of a feigned reconcilement, which rendered him still more dangerous.
The king of Navarre, insolent from past impunity, and desperate from the dangers which he apprehended, continued his intrigues; and associating himself with Geoffrey d'Harcourt, who had received his pardon from Philip de Valois, but persevered still in his factious disposition, he increased the number of his partisans in every part of the kingdom.

He even seduced, by his address, Charles, the king of France's eldest son, a youth of seventeen years of age, who was the first that bore the appellation of "dauphin," by the reunion of the province of Dauphiny to the crown.

But this prince, being made sensible of the danger and folly of these connections, promised to make atonement for the offence by the sacrifice of his associates; and in concert with his father, he invited the king of Navarre, and other noblemen of the party, to a feast at Rouen, where they were betrayed into the hands of John.

Some of the most obnoxious were immediately led to execution: the king of Navarre was thrown into prison;[*] but this stroke of severity in the king, and of treachery in the dauphin, was far from proving decisive in maintaining the royal authority.