Popeye's appearance is based on a fighter named Francis "Rocky" Fiegel that E.C. Segar used to know. Because of this, a tombstone was put on his hitherto unmarked grave in 1996. Segar paid Fiegel a small fee for the use of his likeness, as he was still alive when Popeye first appeared.
To ensure that people watched this short, it was marketed as a Betty Boop vehicle, and she makes a small cameo appearance in the movie. However, the main character is Popeye as suggested by the short's title.
In addition to Popeye being based on Rocky Fiegel, Olive Oyl and Wimpy also are based on real people. Wimpy is based both on E.C. Segar's former newspaper editor, Bill Schuschert, who was a great hamburger lover, and on an underhanded fight promoter whom Segar used to know. Olive Oyl was based on a schoolteacher named Dora Paskal, who was tall, wore her hair in a bun, and wore high-bottom boots just like Olive. She appeared in the comic strip Thimble Theater long before Popeye did. (Her original beau was a cowboy named Ham Gravy.)
When new animated Popeye cartoons were made by King Features in 1960 and 1961, the producers thought Bluto had been created for the Fleischer Studios shorts and that they didn't have the rights to the character, so they renamed him Brutus. (Bluto actually had appeared in a single adventure in the comic strip before any animated Popeye cartoons had been made.) The name Bluto was used again for certain animated Popeye cartoons after 1961.
Many critics have noted how Popeye predates Superman by 10 years. (Popeye made his first appearance in the Thimble Theatre comics in 1929; Superman made his first appearance in 1939.) It's also been noted and documented that Popeye was, in many ways, the prototype and inspiration for the Superman character and other superheroes that followed, in that he was an ordinary human who would suddenly gain superhuman powers by the use of a device (eating spinach).