I've been writing these short little blurbs on various deities for a Facebook group I belong to, and figured I might share some of them here, as well.
Polymnia, or Polyhymnia, whose name means many praises/hymns, is a Greek goddess, youngest of the nine Mousai, or Muses. Her sphere of influence is that of hymns, prayers, and sacred poetry and song. She also has ties to agriculture. Her symbols were a veil, scroll, and grapes.
Ouranie, or Urania, whose name means heavenly or celestial, is a Greek goddess, eldest of the nine Mousai, or Muses. Her sphere of influence is that of astronomy, and she also enjoys philosophy. Her symbols are a globe and stylus. Renaissance artists would often depict her with a crown of stars, and interestingly, it was also during the renaissance that she became a muse to Christian poets.
Kleio, or Clio, whose name means "to make famous," or "to celebrate," is a Greek goddess, one of the nine Mousai, or Muses. Her sphere of influence is that of history. Her symbols are scrolls, books, a laurel wreath, and the cornet, a brass instrument. She was perhaps given the title of "the Proclaimer."