The role of Welshmen in the affairs of England in the fifteenth century was shaped, above all else, by the events of its first decade. Henry IV had leant on his Welsh estates to secure his path to the throne and as king had added them to the royal demesne. The shires of the principality were granted to his son, Henry of Monmouth, but the effect was to place approximately two-thirds of Wales under royal control. The apparently secure hold over the royal demesne in Wales was soon challenged. Owain Glyndŵr, esquire and a Welsh baron of princely descent, began a rebellion that lasted about ten years and defined Anglo-Welsh relationships for the remainder of the century. The military experience won in the course of the rebellion by both the prince and the Welsh leaders was an important factor in the manner in which England fought its wars in France and the shape of Welsh society.

The first part of this chapter considers the military response to the rebellion within Wales and by Welshmen as well as Englishmen. It goes on to address the process of reconciliation between the end of the rebellion and the end of Henry V’s reign in 1422. All Welshmen were touched by the rebellion and most would have had some sort of military involvement with it: as a result, Wales was remilitarised. As in the period after the Edwardian conquest, Welshmen could be treated as a military resource but a resource that was difficult to trust. The second part of this chapter examines the way in which the English government went about using the experience of the rebellion. After the rebellion, military service was part of a wider process of reconciliation and accommodation. Former rebels served in England’s armies alongside those who had remained loyal to Henry IV and his son, the prince of Wales. The reconciliation of former rebels is an important theme in the second part of this chapter and is discussed in relation to the earl of Arundel's expedition to France in 1411 and Henry V's expedition in 1415. Finally, there is a consideration of how Welshmen made military careers after the rebellion in the invasion of France. This chapter is therefore, a study of rebellion, resistance and reconciliation.