Leo I may refer to:
People Pope Leo I (400–461), also known as Pope Saint Leo the Great Leo I (emperor), Roman emperor from 457 to 474 Leo I, Prince of Armenia (d. 1140) Leo I, King of Armenia (1150–1219), sometimes also referred to as Leo II, or Levon I the Magnificent, first king of Cilician Armenia
Other LEO (computer), first computer used for commercial business applications Leo I (dwarf galaxy), a dwarf galaxy that orbits the Milky Way Galaxy, and can be seen in the constellation of Leo The Leo I Group, a group of galaxies also known as the M96 Group
See also Leo II (disambiguation)
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