When Walt Disney first came up with the idea for his soon to be world famous Mouse, he had what he thought was the perfect name for him- Mortimer Mouse. Luckily for him, his wife Lillian came up with a more marketable name- Mickey Mouse.
Lillian had felt that the name Mortimer sounded too stuck up for a cute little mouse. So when his staff had an idea for a stuck up rival for Mickey, Walt thought back to Lillian’s warnings about using the name Mortimer- and realized that it would be the perfect name for Mickey’s rival.
The character has been used many times throughout the years.