The king's army was nearly twice as big as the rebel army. The battle began when the Baronial forces attacked the king's . When the fighting started, it looked as though the king's army would win easily. Prince Edward, who was only 25, was headstrong and made one big mistake. Edward was in charge of the cavalry, who did well in the battle but then chased some of the rebels who were running away. By the time they came back to the battlefield, the rebels had managed to win the battle. With Edward off chasing foot soldiers, Henry was forced to attack using his two remaining divisions. Henry led one, the other was led by his brother, Richard, Earl of Cornwall. Henry's division fought until driven back by the Baronial reserve forces. Cornwall's division did not do well from the start. Cornwall fled the field and hid in a windmill but was quickly captured by the barons. As a result of the battle, King Henry III was forced to sign a document called the Mise of Lewes. This gave the rebel barons what they wanted. A year later the barons were defeated at the Battle of Evesham.