Gaspard wrote in an Italianate manner for an airy 4-part texture; his style shows great euphony and harmonic clarity, though he was also skilled in canon and the notational intricacies of Northern music. He wrote some eight Masses, two Credos, twenty-eight motets, two motet cycles and five chansons that survive; the rnotet cycles were early examples of pieces intended to be substituted for the Proper (i.e. those texts which change according to the liturgical feast etc.) of the Mass. Five of his masses were issued by Petrucci, the first music printer, in Venice (early 1500s), who concentrated heavily on the contemporary third generation of Flemish Polyphony.
This highly esteemed member of the third generation of Flemish Polyphonists, championed by Josquin, played a part in the diaspora of “Fiamminghi” (from the Low Countries) in Italy, which entered Italy (passing the Alps, hence also called “oltremontani”) in 1402 when Johannes Ciconia from Liège chose (his last) residence in Padua.
When duke Galeazzo Maria Sforza prepared the founding of the Lombard court chapel in Milan (in 1473), he first attracted Gaspard van Waarbecke in 1473 and had him travel back north twice, in 1472 and 1473, to recruit more Flemish musicians, notably the composers Josquin Desprez, Loyset Compère and Johannes Martini. Gaspard himself later sang in the Papal choir in 1481–9 and between 1499 and 1515; in the 1490s he made a triumphal return to his native Flanders.
[This contribution is mainly based on KULeuven’s musicology professor Ignace Bossuyt’s book “De Vlaamse Polyfonie” and the HOASM site which links below.]