There is only one way to make sense of Jeanne’s marriage to Charles of Navarre. Although it was extremely possible that Jeanne of Navarre ( two Jeannes!—see diagram) was illegitimate, the was also a chance that she carried the Capet blood line. By marrying his daughter to Charles, King John was ensuring that no other royal house could acquire a claim to the Navarrese throne or the Capet blood lines .
Having made the marriage Jeanne’s role must have been difficult, She was married to a man who was determined to seize her father’s throne.