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.