Upon the usurpation and accession of King Henry IV in 1399, many of those titles were placed under attainder, due to the complicity of their holders in the murder of the Duke of Gloucester.

They met on 17 December 1399 at the Abbey house in Westminster and plotted to capture the new King Henry IV while he was at Windsor for the feast of Epiphany.

However, Edward of Norwich betrayed the conspirators to King Henry, although according to Tait, contemporary English sources which describe the conspiracy make no mention of Rutland, and his role in it is open to doubt.

Kent and Salisbury arrived at the castle with a force of about 400 men-at-arms and archers, but hearing that the king, forewarned, was no longer there, quickly left.

Those executed were subsequently attainted in March; the brother of Kent and the sons of Salisbury and Huntingdon were later restored to their fathers' titles.