Treaty of Wallingford secures her son's succession

On 6 November 1153, King Stephen and Matilda's son, Henry of Anjou (later Henry II), agreed to the Treaty of Wallingford (also known as the Treaty of Winchester), a landmark settlement that brought the civil war known as the Anarchy to an end. Under its terms, Stephen was permitted to retain the crown for the remainder of his life, but formally recognized Henry as his adopted son and designated heir, bypassing Stephen's own surviving son Eustace's claims (Eustace had died shortly before the treaty).

Though Matilda herself was not a direct party to the negotiations, having withdrawn to Normandy some years earlier to manage her estates and support her son's cause from the continent, the treaty represented the ultimate vindication of the succession she had fought for since 1139. Her decades of persistence — through military campaigns, sieges, and diplomatic maneuvering — had kept her family's claim alive long enough for her son to inherit the throne through negotiation rather than continued warfare.

When Stephen died less than a year later, in October 1154, Henry acceded peacefully as King Henry II, founding the Plantagenet dynasty that would rule England for over three centuries. The Treaty of Wallingford thus stands as the true resolution of the succession crisis Matilda had championed, transforming her personal claim into a dynastic triumph achieved through her son.