On 2 February 1141, Matilda's forces defeated and captured King Stephen at Lincoln, opening the way to her ascendancy.
On 2 February 1141, forces loyal to Matilda, led by her half-brother Robert, Earl of Gloucester, alongside allied barons including Ranulf, Earl of Chester, decisively defeated King Stephen's army at the Battle of Lincoln. Stephen fought bravely, reportedly wielding a battle-axe after his sword broke, but was ultimately captured and taken prisoner.
Stephen's capture was a seismic event in the civil war: it removed the reigning king from the political stage and, for the first time, gave Matilda's faction a genuine, uncontested opportunity to establish her as ruler. Stephen was imprisoned at Bristol Castle, and Matilda's supporters moved quickly to capitalize on the victory, securing the allegiance of the Church, including that of Stephen's own brother, Henry of Blois, Bishop of Winchester, who initially recognized Matilda as 'Lady of England and Normandy.'
This victory represents the high point of Matilda's military fortunes and directly enabled her subsequent, though short-lived, period of ascendancy in the summer of 1141. The Battle of Lincoln demonstrated that the civil war could be won on the battlefield, and it is remembered as one of the pivotal engagements of the Anarchy, fundamentally reshaping the balance of power between the two rival claimants to the English throne.