Solfèges à deux voix égales: notes on a Rousseau manuscript

The Houghton Library at Harvard University preserves an autograph manuscript by Jean-Jacques Rousseau entitled Solfèges à deux voix égales. The manuscript consists of 14 leaves and comprises a collection of 13 numbered pieces for two unaccompanied treble voices. It contains 12 duets, labelled solfège, for which no authorship is given, followed by a duo attributed to Jean-Joseph Cassanéa de Mondonville. Apart from sporadic references, this manuscript does not seem to have drawn any particular attention from musicological scholarship. This article surveys the contents of the manuscript in order to provide some insights into the Solfèges à deux voix égales, with a view to encouraging further research into their relationship with Rousseau’s musical activity and thought. This source not only sheds light on certain aspects of the 18th-century solfeggio tradition, but also offers new insights into the crucial role played by music in Jean-Jacques Rousseau’s complex and multifaceted personality.