No study of late medieval treason would be complete without an investigation of that class of offences which was referred to contemporaneously as misprision. The treatment of this topic by modern historians has been at once both exiguous and unfortunate, more so even than that of treason itself. One error has been to hold misprision as almost the equivalent of treason, another has been to take the Tudor usage of the word and apply it to the crimes of the fourteenth and fifteenth centuries. Initially the word misprision had no strong or special connexion with treason. Tudor statutes may refer to ‘misprision of treason’ but the records of the later middle ages contain not a single example of the phrase: in them it is always misprision tout court. The popularizer of ‘misprision of treason’ was probably Sir Edward Coke. In the Institutes of the Laws of England he separated ‘misprision of treason’ from ‘misprisions divers and severall’ and awarded it a separate if slender chapter.

Coke was led into error in both chapters by his unsound critical apparatus. He elected to commence his investigations by means of etymology. ‘Misprisio’, he wrote, ‘cometh of the French word mespris which properly signifieth neglect or contempt: for mes in composition in the French signifieth mal as mis doth in the English tongue: as mischance for an ill chance and so mesprise is ill apprehended or known. In legall understanding it signifieth when one knoweth of any treason or felony and concealeth it'. In fact the proper meaning of the word was not a neglect or contempt but a mistaken or wrongful action.