It is well known that Henry V's conquest of Normandy (1417–20) marked a major shift in English war policy. There is no earlier parallel for the occupation of territory on this scale. Although thirty years later the venture failed in a manner which did much to trigger civil unrest in England, this should not cloud the achievement of conquering and holding Normandy in the first place. By all standards, Henry V was an effective military commander. He was also astute in his political dealings with conquered peoples, carefully navigating between conciliation and control. Key to this was the maintenance of discipline in his armies. The Burgundian chroniclers, Enguerran de Monstrelet, Jean de Waurin and Jean le Fèvre (who had experienced Henry's leadership at first hand when accompanying the English army from Harfleur to Agincourt in 1415), ascribed Henry's success in France to his firmness in dealing with his soldiers. The principal reason was that he punished with death without any mercy those who went to the contrary and infringed his commands or orders, and he fully maintained the discipline of chivalry as the Romans did of old.

The earliest known set of disciplinary ordinances for an English army belongs to Richard II's campaign to Scotland in 1385 but there is enough to suggest that Edward III had issued some ordinances in 1346. That Henry V issued ordinances for his expeditionary armies of 1415 and 1417 is not doubted although we cannot be sure which of the surviving texts belongs to which date. We also have ordinances issued by Henry at Mantes in either 1419 or 1421. All of these texts were for expeditionary armies serving in the field. None includes clauses in anticipation of establishing garrisons. We must ask, therefore, whether these ordinances would be useful once garrisons were established in Normandy. Some of the clauses would be applicable whatever the context. These include the ban on soldiers from attacks on churches and from raping women as well as clauses relevant to any military situation, such as obedience to a superior officer and the prevention of disputes between soldiers. Overall, the ordinances for expeditionary armies were concerned with discipline within the host rather than with relations between soldiers and civilians. Central to their implementation were the captains as well as the constable and marshal of the army as a whole.