Peter the Cruel

Peter I's conflict with his half-brother Henry of Trastamara escalated into a full-scale civil war. The war divided Castile between supporters of Peter and Henry, with involvement from France and England as part of the Hundred Years' War.

Peter I formed an alliance with Edward the Black Prince of England, who led an army into Castile to restore Peter to the throne after he was deposed by Henry. The alliance brought English military support but at a high financial cost.

Peter I and Edward the Black Prince defeated Henry of Trastamara's Franco-Castilian army at the Battle of N

Peter I was captured and killed by his half-brother Henry of Trastamara after the Battle of Montiel. Henry personally stabbed Peter to death, ending the civil war and establishing the Trastamara dynasty in Castile.