Gioachino Rossini was 71 years old when he composed the Petite messe solennelle in 1863; this most celebrated of opera buffa composers had not issued a single new opera in over three decades, and it had been a full 51 years since his music was first head at La Scala. But Rossini's hand was not at all rusty, even though he spent the 1830s, 1840s, and 1850s in comparative retirement, dabbling only occasionally in this odd piece or that one. There are even those who consider this mass to be Rossini's most finely-crafted effort. Rossini composed the Petite messe solennelle for a private performance at the home of the Count Michel-Frédéric Pillet-Will and his wife Louise in Paris, and he scored it accordingly, using 12 solo and semi-solo singers, a pair of pianofortes and harmonium. A few years later Rossini orchestrated the work, not for any specific occasion but simply because he feared that if he didn't, someone else might, and that idea was as unacceptable to him as it has been to countless other composers over the generations.
The Petite messe solennelle is really not all that petite: it fills over 150 pages in its chamber version and covers all of the necessary Mass ordinary material at full length. The deployment of the soloists throughout the 16 musical numbers is varied: sometimes, as in No. 5 "Domine Deus" for tenor solo, No. 10 "Crucifixus" for soprano solo, and No. 15 "O salutaris hostia" for soprano again, a single soloist is left completely alone in an aria-like number; sometime the small chorus remains to back up a soloist; and yet other times the four soloists work together in the traditional vocal quartet fashion. Never, however, does the chorus get a number all to itself.
Rossini had a fine sense of humor (could he have written the operas he did without one?), and the manuscript to the score contains many wryly self-deprecating little written notes, including an apology to God for the shortcomings of this "poor little mass" and a note remarking that, unlike the 12 disciples, none of his 12 singers will "sing falsely"! But the mass is in no way meant to be a comedy; it is a serious piece, honestly and deeply felt in an innocent, straightforward way. If some of the passages sound as though they might have come from a light opera, well, Rossini's apology explains that that's just Rossini doing what Rossini did best, hoping that the God for whom he wrote the piece would give him the benefit of the doubt. The Petite messe solennelle joins Rossini's Stabat mater of some years earlier as a vital, yet all-but-unknown, piece of the nineteenth century European sacred music puzzle.