Captain Marvel (DC Comics) abilities. Based on book sales, the character was the most popular superhero of the 1940s, outselling even Superman. Fawcett expanded the franchise to include other "Marvels", primarily Marvel Family associates Mary Marvel and Captain Marvel Jr., who can harness Billy's powers as well. Captain Marvel was also the first comic book superhero to be adapted into film, in a 1941 Republic Pictures serial titled "Adventures of Captain Marvel". Fawcett ceased publishing Captain Marvel-related comics in 1953, partly because of a copyright infringement suit from DC Comics, alleging that Captain Marvel was a copy of Superman. In 1972, DC licensed the
Captain Marvel (DC Comics) Marvel Family characters from Fawcett, and returned them to publication. By 1991, DC had acquired all rights to the characters. DC has since integrated Captain Marvel and the Marvel Family into their DC Universe and has attempted to revive the property several times, with mixed success. Due to trademark conflicts over another character named "Captain Marvel" owned by Marvel Comics, DC has branded and marketed the character using the trademark Shazam! since his 1972 reintroduction. This, in turn, led many to assume that "Shazam" was the character's name. DC later officially renamed the character "Shazam" when relaunching its comic book