This fragment is apparently the only surviving remnant of a late 15th-century choirbook of unkown extent and contents. Copied by a single scribe; as in EtonC 178 and LonLP 1, the text is written partly in black, partly in red ink, to indicate the distinction between 'full' and 'solo' sections. Probably copied at Canterbury Cathedral. During the reign of Elizabeth I, this half-leaf was used as a cover for a volume containing the record of an archidiaconal visitation of the Deanery of Westbere, northeast of Canterbury. The verso of the leaf faced outward, and formed the front of the book; the insctiption ' Lib. 3 / Decan: Cantuar: x Westbere / 1560' was added. At present, the half-folio is part of a collection of miscellaneous leaves from various music manuscripts preserved under the call number 'Additional 128'.
voices are laid out in cantus collateralis