Battle of Formigny The Battle of Formigny ( 15 April 1450 ) was a battle of the Hundred Years ' War fought between England and France . It was a decisive victory for the French . Background . The French , under Charles VII , had taken the time offered by the Treaty of Tours in 1444 to reorganize and reinvigorate their armies . The English , without clear leadership from the weak Henry VI , were scattered and dangerously weak . When the French broke the truce in June 1449 they were in a much improved position . Pont - Audemer , Pont - L ' Evêque and Lisieux fell in August and much of Normandy was retaken by October . Cutting north and east the Bureau brothers oversaw the capture of Rouen ( October 1449 ) , Harfleur ( December 1449 ) , Honfleur and Fresnoy ( January 1450 ) , before moving on to invade Caen . The English had gathered a small army during the winter of 1449 . Numbering around 3 , 000 men , it was dispatched from Portsmouth to Cherbourg under the command of Sir Thomas Kyriell . Landing on 15 March 1450 , the army was reinforced with a further 2 , 000 men under Sir Matthew Gough in late March . Battle . Kyriell advanced south and captured Valognes in a bloody clash , as further south two French armies joined ( around 5 , 000 men under Charles I de Bourbon , who was also Comte de Clermont ) and marched north for Carentan . The English army circled Carentan on 12 April , the French declined to sally although there were a number of smaller skirmishes . Kyriell turned east towards Bayeux , reaching the village of Formigny on 14 April . At the same time a third French force , under Arthur de Richemont , had reached Saint - Lô from the south . On 15 April , Clermont ' s forces were sighted by the English . The armies faced each other on the Carentan - Bayeux road , near a small tributary of the Aure , the English with their backs to the stream . The English formation numbered around 4 , 000 – with a three - to - one preponderance in archers – and gathered in a long line behind a thicket of stakes and low earthworks . Clermont opened the engagement with attacks against the flanks and small charges ; these had little chance of success and were easily turned away . He then advanced two cannon s . After a period of fire that caused a few casualties , the English charged and captured the guns . These initial skirmishes took some three hours . At this time the Breton army under Arthur de Richemont arrived from the south , having crossed the Aure and now approaching the English force from the flank . They numbered almost 1 , 200 Bretons – almost all mounted judging from the pace of their march . Kyriell drew back from Clermont and shifted his force into an " L " , straddling the stream . With the prepared position abandoned and split by the enemy ' s firepower the English force was soon overwhelmed in a series of charges . Kyriell was captured and his army shattered . Aftermath . The English had been dealt a major blow , 2 , 500 killed or seriously wounded and 900 taken prisoner while French and Breton casualties were no more than 1000 dead and wounded . With no other significant English forces in Normandy , the whole region quickly fell to the victorious French . The advance continued elsewhere , quickly sweeping up all English possessions except Calais . 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 well . The cannon may have been decisive , not so much for the effect they had themselves , but in that they alerted Richemont to the fact that there was a battle going on , and so caused his appearance on the field . It was fortunate for Clermont that this was so because one of his captains wrote shortly afterwards that if the Constable ( Richemont ) had not come when he did , Clermont ' s army would have suffered " irreparable damage " .