Heinrich Isaac was a native of Flanders, but took the opportunity to start his career as a singer-composer in Florence in the 1480s, possibly recruited by Lorenzo de’ Medici. As one of the ‘Singers of San Giovanni’ he was involved not only in liturgical music, but also as part of the Medici’s private and public use of the arts for entertainment and representation of status.

Isaac’s duties included providing the court chapel with liturgical repertoire, and it seems the Missa Wohlauff gut Gsell von hinnen is based on an earlier mass that uses a popular song, Comment peult avoir joye? Isaac may indeed have known the Josquin setting that is also included in this programme, and re-purposing such material was common practice at the time. In this case most of the previous four-voice Mass settings were used in a different order, given new texts, split up, developed and expanded with new sections, using the luxury of six-voices to create one of Isaac’s longest and most impressive Mass settings. Numerous compositional techniques are thrown in, with the original melody used at every position in the vocal range of the piece and in all kinds of canonic polyphony. All of this adds up to a really rather overwhelming experience. Each line is given clarity by the single voice to a part Cinquecento, but the blending of sonorities in the whole make for wonderful listening, with waves of collective voices and the emergence and receding of individual lines creating something truly glorious.

I’m not sure if this is good advice, but you can tune your ears in advance of the Mass by first playing track 22 and Josquin’s setting of that melody Comment peult. Even here there is a sophistication at work that makes picking out the tune by no means the easiest thing in the world, and Isaac’s Mass takes this material into realms that allow us to ignore tune-spotting if you don’t feel the need. At nearly 42 minutes this Mass is a substantial and immersive listen, but at 21 tracks each section is short in average duration, and there is therefore a good deal of contrast along the way. Texts are printed in the booklet in German, Latin as sung, and English. If you need any convincing with regard to the qualities of this Mass, have a listen to the scrunchy harmonies in the second Kyrie on track 3, or the beautiful Sanctus on track 13. The three sections of the final Agnus Dei are also breathtaking, but any moment in this stunning masterpiece may leave your jaw dropped or bring a tear to your eye.

I’ve had a look around but couldn’t find any current alternatives on record to Isaac’s Missa Wohlauff gut Gsell von hinnen, so acquiring this disc will enter you into a pretty exclusive club. Separated by the Josquin Comment peult, the rest of the programme is taken up with three of Isaac’s motets, and these are by no means mere fillers. David J. Burn’s excellent booklet notes indicate that some of the music has been attributed to other composers, and the final Judea et Jerusalem may indeed be by Jacob Obrecht. None of this detracts from the sheer quality of what we hear, aptly summed up in the notes as music that 'illuminates the sacred mysteries of its text from the inside.' Such illumination would not be possible without the superb voices of Cinquecento, and Hyperion’s excellent recording, which is perfectly balanced in a spacious acoustic, but close enough for that all-important clarity of diction and line to be communicated without any need to strain the senses.