In Morte Darthur, Malory employs two distinct modes of the word ‘treason’. In one mode, the senses and applications of the noun ‘treason’ are extrapolated from the ways in which Malory assimilated legal terminology and in which the definition of ‘treason’ is founded in the English statute law 25 Edward III Statute 5 (the Treason Act of 1351). Malory developed the other mode from his French source texts, which in turn based their use of ‘treason’ on the way it was understood in thirteenth-century France. I propose to call these two modes of Malory's respectively ‘legal’ and ‘literary’. The first objective of this essay is to examine Malory's uses of the vocabulary of treason. The second objective is to examine the ways in which this dual usage of the language of treason impacts upon the movement and message of the final two books: ‘Launcelot and Guenevere’ and the ‘Morte Arthur Saunz Guerdon’.

The Treason Act of 1351, quoted at length since it is referred to regularly in this article, defines treason as occurring when