The dream of Admiral Yi Sun-sin: The earliest known case of the invention made in a dream, belongs by the end of the XVI century. Admiral Yi Sun-sin ordered the Korean navy during Japanese invasion in 1592. Japanese could destroy a set of the Korean ships. Once the monster dreamed the admiral: a sea turtle with the head of the dragon, throwing out a fire from a mouth. No swords could punch an armor of a turtle. Having woken up, Yi ordered to shipbuilders to construct a vessel of the thick pine logs upholstered with the iron reservation. The rostrum was executed in the form of the head of a dragon, from his mouth the gun shot. The small fleet of these first-ever battleships reflected attack of enemies.