Atlantis is a fictional island mentioned in Plato's works Timaeus and Critias as part of an allegory on the hubris of nations. By describing Atlantis as a naval empire from the west that had conquered most of Europe and Libya, Plato purposely created a literary contrast with the Achaemenid Empire, the great land-based power that ruled the east. In Plato's account, Atlantis loses divine favor after an ill-fated campaign against a fictionalized Athens, and subsequently submerges into the Atlantic Ocean. By portraying the victorious Athens in the image of his ideal state from the Republic, Plato intended the Atlantis story to bear witness to the superiority of his concept of a state.