In the Rout of Winchester on September 14, 1141 the army of imprisoned King Stephen of England, led by his wife, Queen Matilda of Boulogne and William of Ypres, defeats the army of Stephen's cousin Empress Matilda, whose Angevin forces are commanded by Earl Robert of Gloucester.

This is a major event during the civil war known as The Anarchy, as the captured Robert of Gloucester is subsequently exchanged for Stephen, who is returned to the throne of England, replacing the Empress Matilda.