Du Fay’s Use of Improvisatory Techniques in Resvellies vous et faites chiere lye

While for many years musicologists believed that the art of Renaissance improvisation was lost, recent scholarship has revealed abundant surviving information about historical improvisation in treatises, while musicians have begun to revive these practices.
Research into historical improvisation provides new insight into compositional process, in a period when composers largely worked without scoring up the individual voices on the page. In turn, study of composed works provides insight into how improvisers worked and what they could do.
This article deals with two techniques in Du Fay’s ballade Resvellies vous (Rimini, 1423) that could have been improvised: stretto fuga between discantus and tenor, and the addition of a contratenor to the two-voice framework. The stretto fuga passages in this work are the earliest known examples of the technique. A small group of fifteenth-century Ars contratenoris treatises reveals that improvisation of a contratenor voice was a standard skill for musicians. The author uses rules from treatises and data on Du Fay’s contratenor for Resvellies vous, to explain how an improviser could have looked at the tenor line and improvised a contratenor that works with both cantus and tenor. These findings allow us to imagine how Du Fay himself might have composed the work.