Primera Guerra Civil Castellana
With peace in France, the mercenaries and soldiers lately employed in the war became unemployed, and turned to plundering. Charles V also had a score to settle with Pedro the Cruel, King of Castile, who married his sister-in-law, Blanche of Bourbon, and had her poisoned. Charles V ordered Du Guesclin to lead these bands to Castile to depose Pedro the Cruel. The Castilian Civil War ensued. Du Guesclin succeeded in his object; Henry of Trastámara was placed on the Castilian throne.