Matilda gave birth to her third son William on 22 July 1136 at Argentan, and she then operated out of the border region for the next three years, establishing her household knights on estates around the area. Matilda may have asked Ulger, the bishop of Angers, to garner support for her claim with Pope Innocent II in Rome, but if she did, Ulger was unsuccessful. Geoffrey invaded Normandy in early 1136 and, after a temporary truce, invaded again later the same year, raiding and burning estates rather than trying to hold the territory. Stephen returned to the Duchy in 1137, where he met with Louis VI and Theobald to agree to an informal alliance against Geoffrey and Matilda, to counter the growing Angevin power in the region. Stephen formed an army to retake Matilda's Argentan castles, but frictions between his Flemish mercenary forces 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, promising to pay him 2,000 marks a year in exchange for peace along the Norman borders.