Rout of Winchester 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 , defeated the army of Stephen ' s cousin Empress Matilda , whose Angevin forces were commanded by Earl Robert of Gloucester . This was a major event during the civil war known as The Anarchy , as the captured Robert of Gloucester was subsequently exchanged for Stephen , who was returned to the throne of England , replacing the Empress Matilda . Background . During The Anarchy King Stephen , a nephew of Henry I of England , contended with Henry ' s daughter Matilda ( also called Maud ) for the throne Stephen had usurped . At the Battle of Lincoln on February 2 , 1141 , rebel barons Robert of Gloucester and Ranulf of Chester defeated and captured Stephen . Empress Matilda went on to seize London but its residents forced her out of the city on June 24 . The forces of Stephen ' s queen , also named Matilda ( Matilda of Boulogne ) , soon occupied London . Stephen ' s brother , Henry , Bishop of Winchester , who had earlier defected to Empress Matilda ' s Angevin faction , changed sides again to support Stephen ' s queen . With a small force Henry laid siege to the royal castle at Winchester situated at the southwest corner of the city walls . Empress Matilda sortied from Oxford in late July with a substantial army commanded by Robert of Gloucester . Siege and Counter - siege . On July 31 the Angevin army swooped on Winchester . Bishop Henry fled while his men installed themselves in Wolvesey episcopal castle at the southeast corner of the city walls . While putting Wolvesey under siege , Empress Matilda set up her headquarters in the royal castle , and Earl Robert established his command post at St Swithun ' s cathedral . On August 2 , the bishop ' s men set fire to the city , destroying a large part of it . Queen Matilda quickly assembled an army of relief that included mercenaries hired by Bishop Henry , a levy of the queen ' s feudal tenants from Boulogne , the nearly 1 , 000 - strong London mililtia , William of Ypres ' Flemish mercenary cavalry and other supporters of Stephen . The queen ' s army set up camp on the east side of Winchester and proceeded to blockade Empress Matilda ' s forces in the city . While the queen ' s army was well - provisioned , the Angevin forces soon began to suffer from lack of food . To weaken the blockade Earl Robert attempted to fortify Wherwell Abbey , six miles to the north of the city , but William of Ypres defeated the Angevins with heavy losses . This convinced Earl Robert that he must quit Winchester so he planned an orderly withdrawal . Earl Reginald of Cornwall and Brian fitz Count led an advance guard and protected Empress Matilda . The main body and the baggage followed , Earl Robert commanding the rearguard . The Angevins exited from the west side of Winchester on the Salisbury road . Ahead of them , about eight miles to the northwest , the road crossed the River Test at Stockbridge . As soon as the Angevin host left the city the queen ' s army attacked . They pressed past Earl Robert ' s rearguard to attack the main body . The advance guard avoided the trap and delivered Empress Matilda safely to Gloucester , but the queen ' s army destroyed the Angevin main body as an effective fighting force : only remnants managed to escape . Earl Robert held the rear but when his soldiers reached the Test they could go no further . Surrounded by William of Ypres ' mercenaries and facing a bridge clogged with fugitives , Earl Robert surrendered with his men . Result . The Rout of Winchester was a major setback for Empress Matilda . She exchanged Robert of Gloucester for King Stephen and the latter reassumed the throne . Ultimately , Empress Matilda saw her son Henry II of England crowned king , but Stephen ' s stormy reign lasted until his death in 1154 .