When William Adelin drowned in the White Ship, King Henry I of England was left with no male heirs.

A second marriage to 18-year-old Adeliza of Louvain would produce no children, leaving the widowed Empress Matilda as his only legitimate surviving child.

The first person to swear fealty to Matilda was Stephen of Blois who was the son of Adela of Normandy, the daughter of William the Conqueror.

During this time, Empress Matilda was powerless to act because her husband Count Geoffrey was busy trying to put down a rebellion in Anjou.

[5] Empress Matilda and her party took refuge at Arundel Castle where they were welcomed by King Henry's widow Adeliza and her new husband William d'Aubigny.

At this point Stephen committed an astonishing blunder by giving Empress Matilda a safe-conduct pass to Bristol and withdrawing his army.

The system of justice established under Henry I went to pieces and the common people suffered under the harsh demands of local noblemen and officials.

[6] In December 1140, Stephen began the siege of Lincoln Castle which had been captured by the rebel Earl Ranulf of Chester.

[8] Queen Matilda quickly assembled an army of relief that included mercenaries hired by Bishop Henry, a levy of the queen's feudal tenants from the County of Boulogne, the nearly 1,000-strong London militia, 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.

To weaken the blockade, Robert of Gloucester attempted to fortify Wherwell Abbey, six miles to the north of the city, but William of Ypres defeated the Angevins with heavy losses.

Earl Reginald of Cornwall and Brian fitz Count led an advance guard composed of crack troops designed to protect Empress Matilda.

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.

Surrounded by a part of the queen's troops under William of Surrey and facing a bridge choked with panicked Angevins, Robert surrendered with his men.

At Wallingford another battle was averted when the two parties agreed that Stephen would remain king during his lifetime, but that Henry Plantagenet would succeed him.