We may well wonder which of his works Berlioz – and his contemporaries – understood as “religious.” In the eighteenth century, the phrase “religious music” would have been widely understood as indicating the repertories used in worship services by the Catholic Church and by the various Protestant denominations. It was certainly not music for the concert hall or opera house, since, as everyone knew, these were places of secular entertainment, where at times immodest socializing and even licentious behavior could easily be found. Furthermore, these secular venues were in those years developing the apparatus of the modern public concert scene: the musicians' pay derived from the take at the box office, and thus the audience's curiosity and approval needed to be repeatedly won through newspaper advertising and wall-sized placards, journalists' reviews, and word of mouth. Only one genre – the oratorio – crossed over between these sharply distinct cultural spheres; in the hands of Handel, Haydn, and, in France, Mondonville and Rigel, it brought Bible stories into the hurly-burly of public concert life.

But the oratorio prefigured larger changes within the musical life of the West. The increasing cultural importance of the concert hall and opera house in the decades around 1800 allowed composers and audiences to take more seriously the kinds of music that could be made there; and this frank, if by no means consistent, incursion of seriousness made those places as natural a home as the church for the occasional exploration of religious and other spiritual (philosophical, ideological) thought and imagery.