Bros. for the use of the word "Casablanca" in the film's title due to it being an infringement on the company's rights to the 1942 film Casablanca. Groucho responded with a letter asserting that he and his siblings had use of the word "brothers" prior to the establishment of Warner Brothers (and many others had before that), and often the story is told that Groucho threatened a counter-suit based on this assertion. He also mentioned that he would consider further legal action by pointing out to Warners that the title of their current hit film Night and Day infringed on the titles of two Marx Brothers films were released by MGM: A Night at the Opera and A Day at the Races. The true story is that the original storyline for the film was intended to be a direct parody of Casablanca, with the characters having similar-sounding names to the characters and actors in the 1942 film. Groucho Marx has said that an early draft named his character "Humphrey Bogus", a reference to the leading actor in Casablanca, Humphrey Bogart. Warner Bros. did not litigate, nor threaten to litigate. However, the studio issued a formal inquiry to the Marx Brothers concerning the plot and script of the film. The Marx Brothers exploited the situation for publicity, making it appear to the public that a frivolous lawsuit was in the works, and Groucho sent several open letters to Warner Bros. to get newspaper coverage. These letters were among those he donated to the Library of Congress, and he reprinted them in his 1967 book The Groucho Letters. There is no evidence that Warner Bros. ever responded to any of Groucho’s letters. Ultimately, the matter ended without legal action, and the storyline of the film was changed to be a send-up of the genre rather than Casablanca specifically. The title A Night in Casablanca is a play on the expression of 1929’s "A Night in Venice” starring Ted Healy and his Southern Gentlemen (later The Three Stooges) Moe Howard, Larry Fine and Shemp Howard (later Curly Howard, Joe Besser and Curly-Joe DeRita). References External links The Warner Bros. story at snopes.com The letter to Warner Bros. (broken link) The Marx Brothers Council Podcast episode discussing the film 1946 films 1946 comedy films American black-and-white films 1940s English-language films Films directed by Archie Mayo Films set in hotels Films set in Morocco Films