Out on a limb here. The French National Anthem - La Marseillaise
The sample is in this song by Raven, the title track to their third album All For One, the song is based on The Three Musketeers novel.
The quote from La Marseillaise comes in during John Gallagher's guitar solo at the 2:17 mark.
WARNING: This is serious headbanging metal. Listen at your own risk.
Heard Franz Josef Haydn's St. Anthony Chorale on the radio today for the first time. I instantly knew the theme from a prog album. Had a hard time coming up with the piece of music.
It was Focus's Hamburger Concerto
I've been listening to it for decades but never knew it had classical provenance.
Johannes Brahms also used the piece in his Variations on a Theme of Haydn.
The very last theme in Stravinski's Firebird is used as the opening theme in Manfred Mann's Starbird on The Roaring Silence. The Firebird theme is at the 45 minute mark in this:
I remember when I first bought a copy of the Firebird Suite, I kept thinking that I must have bought something different than the piece that Yes uses as their opening fanfare when performing live, but then at the last minute it finally kicks in.
@KevinJS, I need a little help identifying the classical reference here. I know have it in my vinyl collection. I know it's Slavic. I was thinking Tchaikovsky's Marche Slave, but I think I'm wrong.
The song is from Chicago based doom metal pioneers Trouble from their third album, "Run To The Light". It's called "On Borrowed Time".
You can actually hear it building from the beginning of the song, but the actual reference comes in at the 1:04 mark.
He changed his name from Fryderyk Franciszek Chopin to Frédéric François Chopin, presumably when he was granted French citizenship. (Just looked it up). Didn't realize he snuffed it when he was only 39.