In the grand invocation at the beginning of Book VII of his epic Paradise Lost, John Milton selects as his muse Urania, who is traditionally the Muse of Astronomy in classical texts. He immediately excludes that possible identification, however, when he writes that she is “Nor of the Muses nine.” By calling on her “meaning” rather than her “Name,” Milton relies on a multitude of precedents and traditions, repackaged for his own times and his own idiosyncratic purposes, that critics have consistently failed to recognize or investigate sufficiently. This dissertation looks diachronically at various occurrences of Uranian discourse in literature, historically both before and after Milton, to locate thematic similarities to his works and to help define his Urania accordingly. In spite of her explicit exclusion, the search begins with Urania as Muse of Astronomy because from her mythopoetic genesis in Ancient Greece, other myths are engrafted onto her, most notably Plato’s Uranian Aphrodite as defined in his Symposium. This transformed Urania appears in ancient and medieval cosmic journey and dream narratives and evolves by the Renaissance into an oddly Christianized muse. She becomes a vehicle for heavenly, divine truths that each devout Christian rightly senses in his conscience. In this capacity she promotes friendship and chastity, while she also opposes licentiousness, particularly the lusts of tyrants. In early myths, the Muses are victims of tyranny; but in later appearances, they often sell their patronage of the arts unscrupulously to wicked kings and the flattering poets who are paid by them. Urania’s patronage manages to distance itself from her sisters’ misallocations of inspiration, and parts of the Book VII invocation are clearly an indictment of royal excess. In conclusion, a small group of late-Victorian English poets, mainly from Oxford, call themselves the “Uranians.” Although they too draw from the same traditions as Milton and from Milton himself, they appropriate Urania to satisfy their own political and sexual agendas in a conscious and deliberate revision. / text