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
X-Men (comic book) X-Men (comic book) X-Men is a comic book ongoing series a namesake team of superheroes, published in various incarnations by Marvel Comics, beginning in 1963. The first series was eventually renamed "The Uncanny X-Men" with issue #114 (October 1978). In 1991, a second, companion series debuted, marking the first time, that more than one "X-Men" series would be published. This series took the simpler, earlier name "X-Men", thought it would later be titled "". Volume 3 began publication in September 2010 and for most of its run featured team-ups between the X-Men and other Marvel characters, ended at issue #41