A
quodlibet is a piece of
music which combines several different
melodies in
counterpoint, usually popular tunes, and often in a light-hearted manner. A very famous example of a quodlibet is at the end of
Bach's
Goldberg Variations. Another example is
Galimathias Musicum, a 17 part quodlibet composed by
Wolfgang Amadeus Mozart when he was about 10 years old.
More serious quodlibets can be found in the masses of Jacob Obrecht[?], which sometimes combine popular tunes[?], plainsong and original music at once.