First introduced as Bootleg Pete in 1925's "Alice Solves the Puzzle," from Walt Disney's "Alice in Cartoonland." Originally a bear, Pete was a collector of crossword puzzles, and had his eye on that of the titular Alice's.

Introduced again as Putrid Pete in 1927's "The Ocean Hop," from Walt Disney's "Oswald the Lucky Rabbit." Pete enters as a rival who cheats against Oswald in an airplane race across the Atlantic.

Introduced for a third time as Captain Pete in 1928's "Steamboat Willie," from Walt Disney's "Mickey Mouse Sound Cartoons." Redesigned as a cat, Pete orders his first mate Mickey off of the bridge, and then later puts the mouse to work peeling potatoes after his musical act on the poop deck.

Throughout the 20th century and all the way into the first quarter of the 21st century, Pete continued to be an antagonist or full-time villain for Mickey and Minnie Mouse, as well as Donald Duck, Goofy and Pluto. He would be an ally on occasions, like in the Disney Jr series, "Mickey Mouse Clubhouse." To this date, he remains Disney's oldest and longest running cartoon character.

Note: I did not include Pete from the Universal "Oswald" series since that iteration is not canonically the same that originated in "Alice in Cartoonland," and I strongly believe that a character eternally belongs to the creator.

Pete © Walt Disney