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) of their 1953 settlement. Looking for new properties to introduce to the DC Comics line, DC publisher Carmine Infantino decided to bring the Captain Marvel property back into print, and in 1972 he licensed the characters from Fawcett. Because Marvel Comics had by this time established "Captain Marvel" as a comic book trademark for their own character, created and first published in 1967, DC published their book under the name "Shazam!" Infantino attempted to give the "Shazam!" book the subtitle "The Original Captain Marvel", but a cease and desist letter from Marvel Comics forced them to change the subtitle to