The Nine daughters of Mnemosyne ("Memory") and Zeus, Who preside over inspiration and the arts. From left to right They are: Kalliope, Leader and Muse of Epic Poetry; Melpomene, Muse of Tragedy; Thalia, Muse of Comedy; Terspichore, Muse of Choral Dance, Euturpe (with lyre), Muse of Music; Erato (lounging on steps), Muse of Love or Erotic Poetry; and Polyhymnia, Muse of Sacred Song. Seated in the foreground are Klio, Muse of History (left) and Ourania, Muse of Astronomy.
Original art from a newsletter cover, way back in 1995, back when I was going by the pseudonym Ariadne (as evidenced by the signature in Greek). The medium is pen and ink.