You decide to lay an ambush for his army. Secreting the main part of your mobile forces, you set an advanced battle in plain sight of the Ponthievins. They move to engage the Normans; and according to prior arrangement, this body of your men fakes a rout: count Enguerrand leads a full-speed pursuit. As they pass by the place where you and your command are hiding in the trees, your pursued force turns about and gives fight. Of course, at this point the outcome is certain: with your cavalry you charge into the rear of the Ponthievins. Young Enguerrand is killed and his army destroyed.
This victory assures William of Talou that his king is not going to arrive in time to save him. He capitulates on terms: Arques falls to you, and Talou goes into permanent exile. (Scratch one more enemy.)
A few months pass, then king Henry and count Geoffrey move slowly down the river Seine toward Rouen. Part of their army, commanded by the king's brother Eudes (a man of no military reputation), divides off to attack your lands to the east, evidently planning to encircle Rouen from the north and cut it off from the sea, whilst the king's and count Geoffrey's forces close in from the south.
Now:
Divide your army and feint toward the county of Anjou, hoping to draw off count Geoffrey.
Feint instead toward the Īle de France, to draw off the king.
Withdraw slowly, screening your movements with a small cavalry force, led personally by you; send your main army to attack the eastern force.
Sue for peace.