[2][3] Although cannon had been employed in siege warfare since the early 14th century, Formigny is notable as one of the first recorded uses of field artillery on a European battlefield.

Cutting north and east, the Bureau brothers captured Rouen in October, Harfleur in December, then Honfleur and Fresnoy in January 1450, before investing Caen.

[7] Lack of money and supplies hampered recruiting and lowered morale; in January 1450 the troops lynched an official sent to negotiate with them over pay.

[7] On 15 March 1450, Kyriell and some 2,500 men landed in Cherbourg, where they were reinforced by another 1,800 collected by Edmund Beaufort, 2nd Duke of Somerset, English commander in Normandy.

[6] Rather than immediately relieving Caen as originally planned, Kyriell attacked Valognes, whose possession allowed the French to isolate Cherbourg from the rest of the Cotentin peninsula.

[6][3] Although they did not have time to construct the usual defence works of sharpened stakes, Kyriell was confident since he outnumbered Clermont, and was unaware of Richemont's proximity.

[10] With many of his men busy dragging the captured guns back to their lines, Kyriell shifted forces to the left to face the new threat, while Clermont responded by renewing his attack.

The arrival of the Breton cavalry was arguably more decisive in forcing the English to leave their prepared defensive positions, although the French guns also played a role.

[8] Most significantly, the noise of their firing alerted Richemont to the fact that a battle was taking place and its rough location, so causing his appearance on the field.