The history and significance of the Les Bons Usage et les Bonnes Costumes et les Bons Jugemenz de la Commune D'Oleron has been discussed in chapter 1. The greater part of the Coutumier is unrelated to maritime matters, being concerned with the organisation and economy of the community, but a few chapters are relevant to the present work and those are discussed below. Twiss had the whole text transcribed and translated for his edition of the Black Book and the manuscript was also transcribed but not translated by Bémont in his Coutumier de L'Ile D'Oleron. In his commentary Bémont, working some 45 years after Twiss, remarked that ‘it is necessary to remark that Twiss seems not to have been very familiar with Old French and that his interpretation is not always sound’. This criticism of the first modern scholar to examine the manuscript may be harsh, but it does indicate that a revision of at least parts of his translation is necessary.

Where there was any doubt about a Twiss transcription, it has been compared with Bémont's and, if necessary, revised. Translations considered dubious have been revised, and are included here with chapters of acceptable translation noted as ‘Twiss translation’. In the interests of continuity, chapters of interest have been grouped by subject matter. The transcriptions and translations follow the protocols used in Appendix 1.