Based on nearly two hundred manuscripts containing vernacular glosses, this is the first systematic study of the teaching aids which constituted the set-texts of Latin instruction in thirteenth-century England, some of which are printed here for the first time. These glosses provide the key to discovering the linguistic competence and interest of students at an elementary level: men and women who needed a working knowledge of Latin for practical purposes. The received view that Latin was the exclusive language of the schoolroom is shown to be mistaken and the exhaustive recording of the vernacular glosses provides a hitherto untapped source of lexical materials in French and Middle English.