John Prophet (1356–1416) was an English medieval Secretary to King Henry IV, Keeper of the Privy Seal and, Dean of Hereford and York. A distinguished and capable administrator he remained loyal to all kings through a mix of shrewdness, and cunning. Although guilty of simony and pluralism, Prophet was no lollard, but successfully made the transition from Richard II's extravagant court at Westminster to an indispensable servant of the Lancastrians.