The purpose of this study, ve to analyze the stylistic characteristics in the unaccompanied music of one twentieth century composer, Francis Poulenc, in order to discover the choral problems which would confront choruses and conductors as they performed his music. It is hoped that this study will not only enable choral conductors to better understand, interpret, and appreciate the music of Poulenc, but also will serve as a guide toward the investigation of other twentieth century composers and their works.

In order to trace the origin of the chaconne and passacaglia, the much larger classification of basso ostinato, of which the chaconne and passacaglia are two later examples, must be considered. According to one authority, Lili Propper, the earliest beginnings of the basso ostinato can be traced back to the Middle Ages through the use of organ points exemplified in organum purum. A later and more developed use of the basso ostinato can be discovered in the recurring basses of the Montpellier Codex and the masses of the fifteenth century. A freer manifestation of the idea can be found in the reiterated bass motive of the familiar canon, Sumer is icumen in.