Spring 2019 is set for a bizarre release schedule from Marvel Studios and DC Entertainment, as both studios are releasing big budget superhero films starring characters who are now or once were named Captain Marvel. Yes, both Marvel's Captain Marvel and DC's Shazam! star heroes who were, at one time, called Captain Marvel. In fact, DC's hero came first by a number of decades and was actually one of the most popular superheroes in the history of comic books.
Therefore, you might imagine that the story of how Marvel's upstart hero (who did not even take the name Captain Marvel until 2012) gets to call herself Captain Marvel while DC's hero is now calling himself Shazam would be a complicated one. You would be correct. It is a story involving multiple lawsuits, multiple comic book companies and at least one exploding android.
Like many stories about comic book history, this tale begins with 1938's Action Comics #1, containing the debut of Superman, generally recognized as the first comic book superhero.
Action Comics #1 wasn't just a hit, it was a sort of cultural phenomenon, with Superman appearing in his own nationally syndicated newspaper comic strip by September 1939 (which is sort of amusing, as Jerry Siegel and Joe Shuster only turned to comic books because they couldn't sell Superman to any syndicates as a comic strip) and his own national radio program by February 1940.
Clearly, with success like that comes many imitators and a number of comic book companies started up to try to compete with the publishers of Action Comics (at the time, Action Comics was published by Detective Comics, Inc., which was a sister company of National Allied Publications and All-American Publications. The three companies all did business as DC Comics and eventually they all merged in 1946 to form National Comics Publications. It took decades before the company officially adopted the name DC Comics).
One of the first imitators was Wonderman, a creation of Will Eisner for Fox Publications' Wonder Comics #1 in 1939...
Detective Comics, Inc. sued Fox's parent company, Bruns Publications, Inc. for copyright infringement and was victorious in Detective Comics, Inc. v. Bruns Publications, Inc.
Fawcett Publications, Inc. was a successful magazine publisher that debuted a comic book division, dubbed Fawcett Comics. They launched their own Superman knock-off, Masterman, in Master Comics #1.
Detective threatened to sue and Fawcett backed down.
Then, in late 1939, Fawcett Comics debuted their soon-to-be flagship character, Captain Marvel, in Whiz Comics #2...
And so the troubles began...