It seems you're asking for information about composers. Each of the names you mentioned is a prominent classical composer:
- Mozart (Wolfgang Amadeus Mozart) was an influential composer of the Classical era known for his operas, symphonies, and chamber music.
- Bach (Johann Sebastian Bach) was a composer of the Baroque period, famous for his intricate compositions such as the Brandenburg Concertos and The Well-Tempered Clavier.
- Beethoven (Ludwig van Beethoven) was a crucial figure in the transition between the Classical and Romantic eras, known for his symphonies, piano sonatas, and quartets.
- Chopin (Frédéric Chopin) was a composer of the Romantic era, celebrated for his piano works, particularly nocturnes, études, and preludes.
If you meant to ask who composed a specific piece of music, please provide more details!