This essay focuses on the role of religious works in the oeuvre of Francis Poulenc with an emphasis on his Mass in G (1937) and Gloria (1959). In contrast to the still common view of Poulenc as a light-hearted and somewhat shallow composer, he expressed great emotional complexity in his sacred works. Religion and spirituality were important to his output throughout much of his life. After presenting a history of the religious and political climate in France during Poulenc's youth, I show how his sacred compositions embody certain early twentieth-century philosophies by blending elements of the everyday with high art and tradition with modernity. On the whole Poulenc's works can be understood in terms of what is real, both in inspiration and expression. By incorporating these features, Poulenc redefined the genre of sacred music, expanding its boundaries to allow a more concrete and honest expression of faith.