Who were the Muses in Greek Mythology?

The Muses were the nine daughters of Zeus and Mnemosyne.

Originally there were only three, associated with memory.

Their number was expanded to nine to represent each of the individual arts. They are:

1. Calliope, muse of epic poetry
2. Clio, muse of heroic poetry or history
3. Erato, muse of love poetry
4. Euterpe, muse of music
5. Melpomene, muse of tragedy
6. Polyhymnia, muse of sacred poetry and hymns
7. Terpsichore, muse of choral song and dance
8. Thalia, muse of comedy
9. Urania, muse of astronomy