It's par for the course for biographical movies to mess with the truth to some degree. Sometimes changes are simple. Often, events get compressed together so they take place over a few months -- or years -- rather than decades. Sometimes things take place out of order, or character relationships are modified to add to the drama. These people are making movies, after all.
Considering that P.T. Barnum himself never let the truth stand in the way of a good show, it's probably not all that surprising that The Greatest Showman, the new musical starring Hugh Jackman as the famous promoter, plays fast and loose with the truth in its own way. Here are several events depicted in the new movie that didn't really happen, starting with:
Barnum Uses Sunken Ships As Collateral
Once P.T. Barnum has the idea to build his museum of curiosities, he has to get the money necessary to build it. In the film, this is done by using the deeds to trade ships as collateral to secure his bank loan. Barum commits fraud here, as not only does he not own the ships, but he lost his previous employment due to them all sinking in the South China Sea. In reality, Barnum secured the credit he needed by convincing a businessman to give it to him after he exposed another company's stock issuing scheme. Barnum had actually been in the newspaper business prior to being a showman.
Barnum Meets Tom Thumb and The Bearded Lady As Adults
Once Barnum goes looking for real-life attractions for his museum, he tracks down the people who will be become Tom Thumb, and the Bearded Lady. In the case of Charles Stratton, it's specifically mentioned that the short man is in his twenties, while Lettie Lutz is clearly also an adult. The reality is that the movie has them joining P.T. Barnum decades late. Tom Thumb had been part of Barnum's museum since the age of four, and the Bearded Lady had begun her career as The Infant Esau at the age of one.