Its chief lines ran from Paris:to Le Havre via Mantes and Rouen, to Dieppe via Rouen, to Cherbourg, to Granyule and to Brest.
The king of Navarre, who defended this deed, had, however, many friends in France and was in communication with Edward III.; and consequently John was forced to make a treaty at Mantes and to compensate him for the loss of Angouleme by a large grant of lands, chiefly in Normandy.
At the opening of 1354 he was sent with the cardinal of Boulogne, Pierre I., duke of Bourbon, and Jean VI., count of Vendome, to Mantes to treat with Charles the Bad, king of Navarre, who had caused the constable, Charles of Spain, to be assassinated, and from this time dates his connexion with this king.
The fox (Canis vulpes), the stonemarten (Mantes foina) and the stoat or ermine (Putorius erminea) range in summer above the tree-limit.
A treaty of peace between the two kings was signed in 1365, by which Charles of Navarre gave up Mantes, Meulan and the county of Longueville in exchange for Montpellier.