Hailed as "The World's Mightiest Mortal" in his adventures (and nicknamed "The Big Red Cheese" by archvillain Doctor Sivana, an epithet adopted by fans as a nickname for their hero), Captain Marvel was, based on sales, the most popular superhero of the 1940s, since the Captain Marvel Adventures comic book series sold more copies than Superman and other competing superhero books during the mid-1940s 12. Captain Marvel was also the first superhero to be adapted into film in 1941 (The Adventures of Captain Marvel). Fawcett ceased publishing Captain Marvel and Marvel Family comics in 1953. This was due to both a general decline in the popularity of superheroes and a copyright infringement suit from DC Comics alleging that Captain Marvel was an illegal infringment of Superman. DC licensed the Marvel Family characters and returned them to publication in 1972, and acquired all rights to the characters in 1980. Captain Marvel and the Marvel Family have been integrated into the "DC Universe", and DC has attempted a few revivals. Despite their efforts, Captain Marvel has not regained widespread appeal with new generations, although a 1970s Shazam! live action television series featuring the character was very popular.
Due to the fact that Marvel Comics trademarked their Captain Marvel comic book during the interim between the original Captain Marvel's Fawcett years and DC years, DC Comics is unable to promote and market their Captain Marvel/Marvel Family properties under that name. Since 1972, DC has instead used the trademark Shazam! as the title of their comic books and thus the name under which they market and promote the character. As a result, Captain Marvel himself is sometimes erroneously referred to as "Shazam".