The Preface to the Penitential of Gildas has hitherto been found in only one MS., preserved in the Bibliothèque Nationale in Paris ( = Lat. 3182). This MS. is a large parchment codex of the tenth—eleventh centuries, containing a collection of canons, decretals, penitential fragments, etc. taken from many sources, e.g. the Collectio Canonum Hibernensis, the Lex Salica, etc. After an extract on pp. 279–80 headed ‘Item synodus sapientia sic de decimis disputant’, the Gildasian preface follows on p. 280 with ‘Incipit prefacio Gildae de poenitentia’, concluding on p. 281 with ‘hue usque Gildas incipitnunc sinodus aquilonalis Britanniae’. Most editions of this penitential are reprints of F. Wasserschleben's text. Based on a collation by Dr. Knust, it is defective from the standpoint of readings and palaeographical information.The following collation has utilised, apparently for the first time, a newly-discovered MS. of the penitential, now in the Bibliothèque Municipale at Cambrai ( = No. 625, ff. 52–53). If the catalogue date, viz. saec. ix, is correct, then this MS. is earlier than Paris Lat. 3182.