BY THE THIRTEENTH century the French army stood out as the supreme force in western Europe. The best indication of this is that, after 1214, most of its campaigns took place outside the borders of France. The wars of Louis VIII in the 1220s established royal domination in Provence and Languedoc, areas where it had been weak. Henry III Plantagenet’s attempts to recover his family lands were poorly managed and never in any real sense threatened the Capetian realm. The wars in Guyenne and Flanders at the end of our period were, essentially, the result of French aggression and overconfidence. Edward I had shown no signs of aggression and Philip IV simply seems to have tried to take advantage of his preoccupations within Britain to eliminate his territorial position in France, probably because for a king to do homage to another was always a difficult situation. Elsewhere French armies had conquered south Italy, were active in Frankish Greece, and dominated in the crusader states and Cyprus. This remarkable efflorescence of French power had many complex causes, but it clearly attests to the remarkable success of the French way of war. How and why had that come about?

The French royal army was, in principle, no different from that of any other power of northwest Europe. Medieval armies were very close reflections of the societies that produced them. A relatively poor society dominated by a narrow elite produced a precisely parallel kind of army— in the words of Contamine, an “occasional agglomeration of small autonomous forces.” By the end of the thirteenth century the monarchy had spelled out the military obligation of the population and could raise a much more cohesive force. The outcome of Courtrai was a defeat, but despite that the planning and control exerted by an able commander is very evident. This had come about, however, solely because military service to the monarch had become accepted.

The great nobles remained vital in mobilizing troops from among the petty nobility of their families and their dominions, though increasingly they had to accept the authority of the royal officers who supervised them. The mass of foot was recruited from the cities and the urban militia, augmented by mercenaries when necessary. In addition, a general belief that in time of necessity all freemen had an obligation to serve the king was emerging. The tightening of military obligation so evident in France in the late thirteenth century had English parallels, but no other western kingdom had managed to enforce such provisions so firmly and so widely. The political evolution of the French kingdom made this possible.