For five weeks in late 1399, England's Court of Chivalry was in session to hear a case of treason between Thomas Lord Morley and John Montague, the earl of Salisbury. The dispute between the two men had its origins in the fraught atmosphere of Henry IV's first parliament, where Morley had called Salisbury a traitor for his role in the fall of the duke of Gloucester during the 1397 parliament. Morley had accused Salisbury of betraying the duke's trust by revealing his secret counsel to Richard II and then by falsely appealing the duke of treason; as a result, he had helped to cause Gloucester's death. When the case was initiated, it turned on this charge of personal betrayal of one nobleman by another, an understanding of treason that was firmly grounded in ideas of chivalric loyalty and reflected in Morley's repeated allegation that Salisbury was a faux chivaler. However, when the Court of Chivalry was called into session on 11 November, Morley introduced an addicion that transformed the nature of Salisbury's alleged crime. It included charges that Salisbury had advised and assisted Richard II to destroy the lords and the community of the realm, and other actions ‘against the chose publique and common profit of the realm’. In December, after much legal wrangling, each side stated their final positions. Salisbury denied all the allegations of treason and he then made a striking strategic move by concluding:

The case's denouement came on 5 December, when the court reconvened in the Great Chamber at the king's manor of Kennington. We are told that the parties assembled ‘au cost du lit du roy’, a symbolic use of space that indicates the king himself was present for this final decisive session.