The Battle of Nájera (sometimes called the Battle of Navarrete) took place on April 3, 1367.
With the help of Charles II of Navarre, the Black Prince enters Castile with his army and the certainty of winning victory over the Franco-Castilian troops.
Bertrand Du Guesclin has the necessary experience to defeat the Black Prince:he had fought him several times, he knows perfectly well the value of the tactics employed by the Prince of Wales. But Henry II of Castile refuses to listen to his wise advice, which consists of harassing the adversary and laying traps for this talented enemy in terms of strategy and military tactics. For Henry II of Castile, victory would be achieved by a single battle.
On April 3, 1367, Henry II of Castile disposes his army and gives battle to the English. It's a total disappointment. At the height of the battle, a wing of the Franco-Castilian army suddenly lets go, betrayal or cowardice? The question is not settled. The collapse of the Franco-Castilian troops commanded by Don Tello leads to the capture of Bertrand Du Guesclin and his lieutenants.