French opened the engagement with a failed assault on the English position with their dismounted men-at-arms. French cavalry charges on the English flanks were also defeated. Clermont then deployed two culverins to open fire on the English defenders. Unable to withstand the fire, the English attacked in an attempt to capture the guns. At this moment the Breton cavalry force under Richemont arrived from the south, having crossed the Aure and approached the English force from the flank. Clermont's forces were encouraged by the presence of Pierre de Brézé and stood their ground despite being outnumbered more than twice. As his men were scrambling to capture French guns, Kyriell shifted forces to the left to face the new threat. Clermont responded by pressing the attack. Having abandoned their prepared position, the English force was charged upon by Richemont's Breton cavalry, then enveloped by Clermont and Brézé's French troops, and massacred from both sides, with Kyriell taken prisoner. A small force under Sir Matthew Gough was able to escape. As contemporary chronicles suggest, after the battle, the French infantrymen, despite the knights' protestation, massacred about 500 Welsh archers who were pleading for mercy as their lord, Sir Matthew Gough had abandoned them to escape with his retinue to Bayeux.The English corpses were piled up and buried at the nearby field, later dubbed "The Englishmen Tomb".. Aftermath Kyriell's army had ceased to exist, with 3,754 killed and 1,200–1,400 taken prisoner, while French and Breton casualties were estimated as "probably less than a thousand" or "about 500 men". As all the other significant English forces in Normandy were wiped out before the battle, the whole region quickly fell to the victorious French. Caen was captured on 12 June and Cherbourg, the last English-held fortress in Normandy, fell on 12 August. The battle is often cited as the first in which cannons played a pivotal role (the first decisive use of cannon is generally considered to have been the following battle, at Castillon). This is rather difficult to judge; contemporary accounts are dubious and it can be seen that the arrival of the Breton army of Arthur de Richemont, future duke of Brittany, Arthur III, with his powerful force of cavalry on the flank of the English, forcing them to leave their prepared defensive position, was more significant, although the early artillery fire from the two French guns played a role in that as