 Having no options or allies left Charles II asked for a truce, and by the Treaty of Briones on 31 March 1379 agreed to Henry's demands that he agree to be bound in perpetual military alliance with Castile and France against the English, and to surrender 20 fortresses of southern Navarre, including the city of Tudela to Castilian garrisons.Charles of Navarre's remarkably slippery and devious political career was at an end.He retained his crown and his country but he was effectively a humiliated client of his enemies, he had lost his French territories and his Pyrenean realm was devastated and impoverished by war.