The field of battle was an almost featureless, flat plain. The French army, numbering between 3,000 and 4,000, confronted the much smaller English force who had set up defensive positions by drawing up the supply wagons into a makeshift fortification. The entire defensive formation was then further protected by the placement of sharpened spikes all around to prevent the French cavalry from charging, a tactic which had been employed, with great success, at the Battle of Agincourt. The French attack began with a bombardment using gunpowder artillery, a relatively new weapon for the time and one whose proper usage was not well understood although it was damaging to the wagons and caused English casualties.