The purpose of this edition is to establish the text of the Chastelaine du Vergier, a fifteenth-century prosification of the popular twelfth-century poem, the Chastelaine de Vergi. The edition is based on the only known manuscript, B.N. n. a. fr. 6639. Textual corrections and emendations have been noted and a glossary of unusual words has been provided. From the linguistic evidence presented by the text's orthography, morphology, syntax and vocabulary, the manuscript appears to have been written between 1400 and 1415. The Middle French used by the unknown author/scribe is fairly standard for the period, although certain imperfect subjunctive forms are highly irregular.
A comparison of the original poem and the later prose version indicates that a number of changes have been introduced. The Chastelaine du Vergier has added a scene to explain how the chastelaine and the chevalier came to have a secret relationship. Much of the poem's moralistic and digressive material has been eliminated, and other alterations in the plot also serve to produce a more tightly unified structure. Certain changes in characterization, style and use of dialogue indicate close ties with both the late medieval mise en prose and the fifteenth and sixteenth-century nouvelle. The exemplum of the poem, that love's secrets should not be told, has become a general warning against secrets of all types, including romantic ones. The exact nature of the love shared by the chevalier and the chastelaine is difficult to determine since this text seems to indicate that it is both sinful and innocent. These differences create a problem of interpretation to which some possible explanations have been proposed.