The reign of Henry IV is unique in the history of medieval England in one largely unregarded respect. From his accession until his death the first Lancastrian king was understudied by a single heir apparent. In 1399 Henry of Monmouth, then approaching the age of discretion, was acknowledged as heir to the throne and given the title of prince of Wales. In 1404 the earl of Northumberland publicly swore an oath to be a faithful and loyal liege ‘to our said lord the king and to his eldest son my lord the prince, and to the heirs of his body, and to my lords his brothers and their issue in succession and in line of inheritance to the crown, in accordance with the laws of England’. The period from 1406 until the king's death is especially remarkable in that the English crown was subject to the earliest known statutes regulating the succession. The two statutes of June and December 1406, whose terms were well-publicized, laid down an order of succession including four named lives. The prince of Wales, a member of the council from November 1406, attained his majority in September 1407, and succeeded to the crown on his father's death in 1413. Rather remarkably, no other adult son succeeded a royal father between the accessions of Edward I in 1272 and Charles I in 1625.

It has been observed that from around 1406 the Lancastrian regime was more broadly accepted. The Ricardian cause ‘ceased to articulate a widespread discontent and became instead a vehicle for the irreconcilable grievances of a small but active rump of dissidents.’ Still, the second half of Henry's reign was not untroubled by succession problems, albeit of a different sort. The crucial issues related to the nature of the polity and the transfer of power from father to son. Over the years there has been a great deal of scholarly interest in the political crisis of 1406 and the experiments in conciliar rule that it set in train. Surprisingly little notice has been given, however, to the two acts for the descent of the crown that accompanied it. For the first time the royal succession was made the subject of statute. Even more remarkably, in settling the crown in the male line, the act of June 1406 laid down an order of succession at odds with custom and common law.