Isaac as a Key Figure: Chant-Based Cycles of Propers and Ordinaries

Among the projects through which Maximilian spread the ideology of the imperial house,[2] are Isaac’s cycles of Propers. Though the work was never fully completed, it was intended in its entirety to form a polyphonic Graduale (a book containing the variable, day-specific chants of the Mass) for all occasions and feasts of the church year at the imperial court (» G. Henricus Isaac; » I. Isaac’s Amazonas).[3] The settings, published more than thirty years after Isaac’s death in three volumes under the title Coralis Constantinus in Nuremberg, include Isaac’s compositions of the Introit, Alleluia or Tract, Sequence, and Communion.

Isaac’s twenty-one chant-based ordinaries – cyclical mass settings based on the chant melodies of the individual ordinary chants – also belong to Maximilian’s new approach to ceremonial sonic representation. In several respects, they are extraordinary for the period around 1500: with multiple settings for three to six voices, they not only cover the various festive occasions of the church year (high feasts, feasts of apostles, martyrs, confessors, virgins, Marian feasts, etc.), but in their conception as chant-based ordinary cycles, they also represent the monumentalisation of a genre that had previously led a niche existence.[4] Although individual Mass settings based on the chant melodies appropriate to each section of the Mass had been known since the early fifteenth century, Isaac brought this previously little-regarded form of Ordinary setting to an unprecedented flourishing through his systematic approach to the musical staging of the imperial household’s daily worship, both in terms of genre history and through the incorporation of the latest compositional trends. The musical genre of the Mass thus acquired a representative function for the Habsburgs.

Some characteristics of this type of ordinary mass setting can be illustrated by Isaac’s sonorous six-part Missa paschalis (» D-Ju Ms. 36, fol. 141v–155r).[5] As in nearly all liturgical music of the time, the chant forms the guiding thread around which the polyphonic composition is woven. In this case, it is the first chant-based Mass, used in the liturgy only on Easter Sunday and the Sundays following Easter (until Pentecost) (» Fig. Graduale Pataviense, Kyrie für Ostern). Isaac conceived this composition – as always when setting monophonic Ordinary melodies – as an alternatim Mass, a performance practice in which sections of sung polyphony alternate either with monophonic chant or with improvised organ versets (» Audio example ♫ Kyrie Missa paschalis).[6] The performance with organ improvisations, in which the imperial organist Paul Hofhaimer (» C. Ch. Paul Hofhaimer), a widely renowned improviser, participated, is well documented at the imperial court, for example in the designation of Masses “ad organum” in the Viennese manuscript » A-Wn Mus. Hs. 18745). The music demonstrates an extremely flexible interplay between monophonic chant and polyphony on both vocal and instrumental levels, as well as a close interweaving of vocal and instrumental resources in the liturgical music performed at the court of Maximilian I.

Abb. Graduale Pataviense, Kyrie für Ostern

Kyrie für den Ostersonntag und die Sonntage nach Ostern (bis Pfingsten) im » Graduale Pataviense (Wien: Johannes Winterburger 1511), fol. 184v–185r. (Mit Genehmigung der Bayerischen Staatsbibliothek.)