idea about the growth of armies have been severely criticised by David Eltis as lacking consistency and David Parrott has proved that the period of the trace italienne did not show any significant growth in the size of French armies and that the late period of the Thirty Years War showed an increase in the proportion of cavalry in the armies, contrary to Parker's thesis that the prevalence of siege warfare marked a decrease of its importance. The infantry revolution and the decline of cavalry Some Medieval specialists elaborated on the idea of an infantry revolution happening early in the 14th century, when in some relevant battles, like Courtrai (1302), Bannockburn (1314) or Halmyros (1311), heavy cavalry was routed by infantry; however, it can be pointed out that in all those battles infantry was entrenched or positioned in rough terrain unsuited for cavalry, like in other battles of the 14th and 15th century in which cavalry was defeated. In fact infantry had been victorious in earlier times in similar situations, for instance at the battle of Legnano in 1176, but in open ground infantry still had the worst, as shown for instance at the battle of Patay (1429) and the battle of Formigny (1450) in which the vaunted English longbowmen were easily run down; however, the experience of battles like Courtrai and Bannockburn meant that the myth of the invincible knight disappeared, which was in itself important for transforming medieval warfare. More substance has the case for the "return of Heavy Infantry" as Carey has named it. Pikemen, unlike other infantry, could stand in the open against heavy cavalry. While requiring drill and discipline, individual training requirements were much lower than those for knights, and the switch from heavily armoured knight to footsoldier made possible the expansion in the size of armies from the late 15th century onwards as infantry could be trained more quickly and could be hired in great numbers. But that change was slow. The full development, in the 15th century, of plate armour for both man and horse, combined with the use of the arret (lance rest) which could support a heavier lance, ensured that the heavy cavalryman remained a formidable warrior. Without cavalry, a 15th-century army was unlikely to achieve a decisive victory on the field of battle; battle might be decided by archers or pikemen, but a retreat could only be cut off effectively