The Matter of Britain is the body of Medieval literature and legendary material associated with Great Britain, and sometimes Brittany, and the legendary kings and heroes associated with it, particularly King Arthur. It was one of the three great literary cycles recalled repeatedly in medieval literature, together with the Matter of France, which concerned the legends of Charlemagne, and the Matter of Rome, which included material derived from or inspired by classical mythology.
The three "Matters " were first described in the 12th century by French poet Jean Bodel, whose epic Chanson de Saisnes contains the line:
Ne sont que III matières à nul homme atandant,
De France et de Bretaigne, et de Rome la grant.
There are but 3 matters that no man should be without,
That of France, of Britain, and of great Rome.
The name distinguishes and relates the Matter of Britain from the mythological themes taken from classical antiquity, the "Matter of Rome", and the tales of the paladins of Charlemagne and their wars with the Moors and Saracens, which constituted the "Matter of France". Arthur is the chief subject of the Matter of Britain, though other lesser-known legendary history of Great Britain and Brittany is also covered, including the stories of Brutus of Troy, Coel Hen, Leir of Britain (King Lear), and Gogmagog. (See Legendary kings of the British.)