Superman came before Batman. Superman was created by Joel Shuster and Jerry Siegel in 1933 and made his first official comic book appearance in Action Comics #1, cover-dated July 1938. Created by Bob Kane and Bill Finger, Batman first appeared in Detective Comics #27, cover-dated May 1939.
Superman and Batman are both part of the DC Comics universe. As perhaps the two most iconic superheroes of all time, the characters have enjoyed success in a number of mediums, including live-action television, films and animated series aimed at younger audiences. A copy of Action Comics #1 featuring Superman's first appearance sold for 1 million dollars in 2010.