The Muses

The daughters of Zeus and Mnemosyne, the Titan goddess of memory, the Muses numbered nine altogether. Each of the Muses conquered a particular art:

• Calliope - epic poetry
  
• Clio - history
  
• Euterpe - lyric poetry (flute)
  
• Melpomene - tragedy
  
• Terpsichore - choral songs and the dance
  
• Erato - love poetry (lyre)
  
• Polyhymnia - sacred poetry
  
• Urania - astronomy
  
• Thalia - comedy
  

Source: http://mythopedia.hypermart.net/textonly/mythologies/greek/deities/muses.htm