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,
The History of the Norman Conquest of England written on any historical subject." One exception was General George S. Patton, who in 1944 read Freeman's "History" in advance of the D-Day landings, hoping to learn where to conduct a campaign in Normandy by studying William the Conqueror's choice of roads. In 1953 David Douglas wrote that as a detailed narrative of the Norman Conquest, Freeman's book has never been superseded, and it is those best versed in the history of eleventh-century England who are most conscious of its value. Frank Barlow saw Freeman's influence as being profound. Modern historians, Frank Stenton and Ann Williams among them, have again