If you have a score of Faure's "Requiem" handy, take a look at the keys. There are some interesting connections between his choice of keys and "traditional" key symbolism. For instance, the Introit and Kyrie adhere to D minor, a mournful, somber key (think Mozart Requiem, Bach violin chaconne, Beethoven 9 first movement, etc.).
The Offertory starts around D major in the choral entrance but ends with a transcendent "Amen" in B major - Liszt sonata, anyone? Also, the Sanctus is in E-flat major - three flats, 3/4 time, three iterations of "Holy" in the text - you make the connections.
There is also a very striking reference to F-sharp major around the text "lux perpetua" in the Libera me; this is similar to Liszt's usage again. (In case you're wondering where B major and F-sharp major come in, one can make a case in several Romantic-era works that keys with many sharps signify "light," or "heaven." More on that later, perhaps.)
Just another of the great bonuses made possible by working as a collaborative artist!