Gregorian Chant at the Keyboard: Developments in Plainchant Accompaniment in France and Belgium from 1829 to 1930

From the mid-nineteenth century, Gregorian chant underwent a major revival in France and Belgium. Alongside and intertwined with this revival, important church musicians and chant scholars wrote many chant accompaniment treatises and editions for the organ. While much has been written about the chant revival, comparatively little has been written about the development of chant accompaniment. This dissertation examines key debates found in French and Belgian chant accompaniment treatises from the 1829 introduction of organ accompaniment in Paris to approximately 1930, the end of a particularly fruitful period of development of accompaniment methods connected to Solesmes. Building on the work of Francis Potier and Benedikt Leßmann, it identifies major shifts in the harmony and rhythm considered suitable for accompanying chant. It shows how developments in accompaniment theory are deeply interwoven with the concurrent chant revival at Solesmes and elsewhere in the French-speaking world. It explores transformations in the accompaniment styles of single authors and common disagreements between practitioners in order to identify the values and technical approaches that were considered most essential for accompaniment. Polemics between luminaries including François-Joseph Fétis, Louis Niedermeyer, Joseph d'Ortigue, Jacques-Nicolas Lemmens, Antonin Lhoumeau, Amédée Gastoué, and Henri Potiron offer insight into not only the musical and philosophical details of chant accompaniment theory, but also the important role chant accompaniment theory played in the development of secular music in late-nineteenth- and early-twentieth-century France and Belgium. There has not been a major accompaniment treatise written in English since the liturgical changes of the Second Vatican Council. This dissertation concludes with a brief examination of post-conciliar liturgical principles and considers how, in light of the accompaniment principles from the scope of this study, one might develop a coherent method for accompanying the ordinary chants in the Roman liturgy today.