Stephen, King of England recognised Stephen's son Eustace as Duke of Normandy in exchange for Eustace giving fealty to the French king. Stephen was less successful, however, in regaining the Argentan province along the Normandy and Anjou border, which Geoffrey had taken at the end of 1135. Stephen formed an army to retake it, but the frictions between his Flemish mercenary forces led by William of Ypres and the local Norman barons resulted in a battle between the two halves of his army. The Norman forces then deserted the King, forcing Stephen to give up his campaign. Stephen agreed to another truce with Geoffrey,
Norman conquest of England Count of Penthièvre. In August or September 1069 a large fleet sent by Sweyn II of Denmark arrived off the coast of England, sparking a new wave of rebellions across the country. After abortive raids in the south, the Danes joined forces with a new Northumbrian uprising, which was also joined by Edgar, Gospatric and the other exiles from Scotland as well as Waltheof. The combined Danish and English forces defeated the Norman garrison at York, seized the castles and took control of Northumbria, although a raid into Lincolnshire led by Edgar was defeated by the Norman garrison of Lincoln.