The present composition falls into a circumscribed tradition of polyphonic writing cultivated in the fifteenth and early sixteenth century, namely the Kyrie composed for Easter celebrations, often independently of a polyphonic cyclic mass. At the time of Vourda's composition (c. 1500-1515, judging by dating of the sources and style), this type of Kyrie setting was produced mainly in Germanic regions and the Low Countries.¹ First heard at the transition from the Holy Saturday Vigil to the Easter mass, the Paschal Kyrie represented the announcement of the new festal season, even the start of the new year. Such a composition would continue to be performed at numerous services "in tempore paschali" after the initial mass, securing its association with the liturgical high point of the Christian year.

Vourda's treatment of the pre-existent material in his setting provides an interesting case study in the contrasting cantus firmus techniques current in the first decades of the sixteenth century. The opening measures of the composition present a highly ornamented version of the intonation of the plainchant Kyrie (the well-known melody Lux et origo)² in imitation by the top three voices at the octave and the fourth, so thoroughly elaborated that any identification of the chant would be dubious were it not for the composition's explicit title in the sources and the more traditional unadorned long-note cantus firmus usage later on. The start of the Criste (m. 23) offers precisely this starkly contrasting picture of older "structural" tenor-based writing: the Tenor states a version of the chant with little adornment in longae, breves, and semibreves, while the other voices enter non-imitatively and in shorter note values. In the final Kyrie, the pre-existing material again remains largely confined to the Tenor, but this voice now moves in the same rhythmic values as the others and soon the plainchant is lost in a flurry of decoration - a characteristic transition in cantus firmus composition throughout the second half of the fifteenth century. If the very start of the work, therefore, seems to promise a modern imitation-based rendition of the plainchant Kyrie comparable to the 5-voice Kyrie paschale probably by La Rue, the composition quickly pulls away from this ideal and finally looks considerably more antiquated in its focus on well-established techniques.

Pre-existent material: Plainchant Kyrie Lux et origo, treated as cantus firmus in Tenor and occasional basis of melodic material for other voices

Bruges, Grootseminarie, Gradual, f. 99r

Editorially supplied material: Plainchant sections for 9-fold alternatim performance supplied from the pair of 15th-century graduals of the Grootseminarie in Bruges, ff. 99r and 101r (currently lacking a shelfmark at the Grootseminarie, but sometimes catalogued as MSS D7 and D8).

Notes
[1] A survey of polyphonic Kyrie paschale settings can be found in Theodor Dumitrescu, "The Paschal Kyrie c. 1500: The Compositional Tradition and a New Low Countries Fragment," Tijdschrift van de Koninklijke Vereniging voor Nederlandse Muziekgeschiedenis 58 (2008): 3-31.
[2] For a list of many of the plainchant sources of this Kyrie melody, see Margaretha Landwehr-Melnicki, Das einstimmige Kyrie des lateinischen Mittelalters (Regensburg: Gustav Bosse, 1955), p. 93.