 The French, who had followed all the action from an elevated position from Gerberoy, quickly realized that it was merely an advance party and the main force of the English army was still on the road to Gournay.Since they had not yet sufficiently recovered their strength and repaired the fortifications for the impending siege, the French decided to take the initiative and to attack the Englishmen when they were completely unprepared.A column of French cavalry under La Hire left the town, and bypassed the position of the English vanguard to launch a surprise attack on the English, as they were marching along the road to Gournay.