Openings: c6-c8, lacking c6l (ff. 15r-17r)
Voices: [Triplex], [Medius], Contratenor, Tenor, Primus Bassus, Secundus Bassus
Compass: 23 notes
Cantus firmi: Tenor: Exulat vir optimus: fifth psalm antiphon, Matins, St Thomas of Canterbury (29 December) and at translation of St Thomas (7 July); Primus and Secundus Bassus migrating: 'Cadit custos' (Benham 1987, 467).
Text: RH, 33675: unique to Eton. Also used in E60.
Edition: Musica Britannica 10, 54–63. Harrison's reconstruction was rendered obsolete by Hugh Benham's identification of second cantus firmus. Another reconstruction has been prepared by Timothy Symons and Magnus Williamson for Cantus Firmus Music.