The Unstable Alliances Between John II of France and Charles II of Navarre (1354–1355)

During the Hundred Years' War, John II of France ("the Good") sought to neutralize the ambitions of his son-in-law and cousin, Charles II of Navarre, whose Norman holdings made him a key player in the conflict. Despite repeated attempts at diplomacy, Charles's shifting allegiances and ambitions undermined any lasting peace between them.

The Assassination of Charles de la Cerda and the Treaty of Mantes (1354)

• Charles II of Navarre, ruling a small Pyrenean kingdom, also controlled extensive lands in Normandy, making him a significant power in northern France.
• In 1354, he was implicated in the assassination of Charles de la Cerda, the Constable of France and a favorite of John II.
• Despite this, John II still sought an alliance with Charles II, hoping to secure his loyalty against English expansion in Gascony.
• On February 22, 1354, John signed the Treaty of Mantes, granting Charles new lands and privileges in Normandy in exchange for his loyalty to the French Crown.
• However, the truce between them was short-lived, as Charles continued negotiating with England.

The Treaty of Valognes (1355) and Renewed War

• By 1355, Charles II of Navarre had allied himself with Henry of Grosmont, 1st Duke of Lancaster, one of England’s most formidable commanders.
• To prevent Charles from fully joining the English, John II attempted another reconciliation, leading to the signing of the Treaty of Valognes in 1355.
• However, this peace proved as fragile as the previous one, as the Hundred Years' War escalated again that year.
• Charles II continued to maneuver between the English and the French, playing both sides to advance his own territorial ambitions.

Impact and Legacy

• The Treaties of Mantes (1354) and Valognes (1355) failed to bring lasting peace, as Charles II of Navarre remained untrustworthy and opportunistic.
• His Norman possessions made him a critical player in the conflict, ensuring that his actions deepened instability within France.
• His shifting alliances complicated John II’s war strategy, forcing the French king to contend with both English advances and internal betrayals.

The tensions between John II and Charles II of Navarre were emblematic of the fractured political landscape of France during the Hundred Years' War, where noble rivalries and personal ambitions often outweighed national loyalties.