Monkey Island creator Ron Gilbert has said in the past that the series owes a debt to Disneyland's Pirates of the Caribbean ride and Tim Powers' book, On Stranger Tides – but an eagle-eyed fan has spotted another piece of media which shares some interesting similarities with the point-and-click classic.
As highlighted by @blackhawkadvent, the 1951 film Double Crossbones also features a young rookie pirate, as well as a few sequences that will seem very familiar to fans of Gilbert's first Monkey Island adventure.
For example, in one scene, protagonist and apprentice shopkeeper Davey Crandall (Donald O'Connor) enters a tavern full of pirates with the objective of becoming one after he is falsely accused of being involved in the sale of stolen goods.
Some key sequences from the film are compared with those from The Secret of Monkey Island, and while the similarity between Crandall and Guybrush Threepwood is striking, the general storyline of the movie doesn't really dovetail with that of the game, and, given that Ron Gilbert has stated that he's never seen the movie before, it seems this has to be chalked down to mere coincidence.
Originally entitled Half A Buccaneer, Double Crossbones has faded into obscurity since release, with lead actor Donald O'Connor calling it "one of the worst pictures ever made" prior to his passing in 2003.