Atlantis is depicted as a real location in the fictional DC Comics Universe. The very first DC Universe version of Atlantis debuted in Action Comics #18 (November 1939), and was created by Gardner F. Fox and Fred Guardineer. Other versions appeared in various DC comics in the 1940s and 1950s, including the version in the Superman group of books in which the mermaid Lori Lemaris resides. Aquaman's version of the city, the most prominently featured version in the company's line, first appeared in Adventure Comics #260 (May 1959), and was created by Robert Bernstein and Ramona Fradon. All versions are based on the mythical island of Atlantis first mentioned in Plato's initial dialogue, the Timaeus, written c. 360 BC.