The main focus of the investigation is an examination of the work’s overall structure and the extent to which Marc-Antoine Charpentier has evoked the particular organ genres, registrations and associated musical styles of the various movements that constituted the French organ mass in the seventeenth century. The compositional style of each genre was intimately related to registration. From a total of almost 500 sacred compositions of various kinds, Charpentier’s Messe pour plusieurs instruments au lieu des orgues is certainly one of the most unusual. The circumstances relating to the composition of Charpentier’s Messe have been explored by Patricia M. Ranum. In January 1674, the religious community based at the small Parisian church of Notre Dame de la Mercy et de la Redemption des Captifs decided to purchase an organ. One immediate question concerns the external structure of Charpentier’s instrumental Messe.