Dufay's life seems to have been entirely within the 15th century. He was based at the abbey of Cambrai and seems to have enjoyed a wide reputation spreading as far as Scotland, where one of the manuscripts of this mass survives. The mass is a large-scale work, with a Sanctus lasting over ten minutes (which is a lot longer than, say, Verdi's), and an Agnus Dei taking well over eight. To complete the set there is a motet 'Supremum est mortalibus bonum' dating from the 1430's, and one very intriguing feature of this disc is the presence of an unharmonised 'Veni sancte spiritus' (sung to a popular tune) after the Gloria and two plainsong items 'Jubilate Deo' following the Credo and 'Illumina tu faciem' right at the end after the Agnus Dei. Sadly there is no illumination of this in the liner-note, which is really the most frightful guff saying next to nothing and saying it rather badly. Provisionally I have to assume that these numbers (all short) were sung at appropriate points during the celebration of the mass, otherwise what is the point of sequencing them in this way on the record? What I would have liked some guidance on is whether the composer envisaged these extras as integral parts of the setting of the mass - e.g. do they occur in the manuscripts, of which there are no fewer than four? Evidently I shall have to research this question elsewhere.
I am an admirer of the Oxford Camerata in general. As in their record of Josquin's mass based on the same chanson, there are 12 singers, those male these feminine as Milton puts it, numbering 7 and 5 respectively. I have read some comment that finds them prone to over-slow tempi, but I have been used to 15th and 16th century ecclesiastical polyphony all my life from childhood, and while I have no pretensions at all to being expert on the subject I suppose I can say that I find nothing untoward in any aspect of the Camerata's approach. The recording is predictably good, and the strength of the vocal tone impressed me.
English translations of the Latin are provided for everything here. These are in general accurate, although it is worth pointing out that towards the end of the Veni sancte 'Da...sacrum septenarium' means literally 'grant seven holy years', and 'da salutis exitum' means unequivocally 'grant final salvation'.