The longbow and the crossbow were able to counter the dominance of mounted knights on the battlefield. Although knights of the Middle Ages often fought on foot or at least avoided futile frontal attacks, it happened several times that knightly armies led charges in obeyance to their warrior ideal only to meet with disaster. At Crécy (1346) and Poitiers (1356), the French knights suffered heavy casualties against the Welsh and English longbowmen. The ability to keep several arrows in the air at any given time was an important advantage of the medieval archer. Thus, while a cavalry charge followed a strict pattern of acceleration (400 metres in 2 minutes, gallop at the last 150 metres) from a distance beyond effective missile range, once they came within range they could be met with a hail of arrows that could severely injure both horse and rider alike. However, unsupported light infantry and archers would not be able to cause enough casualties to a cavalry force, if it were charging across suitable terrain, to tip the odds in their favour in the following melee. Thus, it was always advisable for missile troops to fight on terrain disadvantageous to cavalry charges, and with supporting heavy infantry close by.