Bootlegs turning out to be the originals

After reading a certain online profile last week and doing some research about Heathcliff the cat, I was surprised to discover that he actually predated Garfield! My world was flipped upside down. Growing up, I had always considered Heathcliff to be the bootleg, grungy version of Garfield, a low-end knockoff (with an amazing intro). Then today, while typing one of my favorite exclamations, "Heavens to Murgatroyd!", I looked up the spelling of it and found out that Snagglepuss predated the Pink Panther! What is going on here? I guess it never made total sense that the most popular necessarily had to be the original, but still...Are there other characters like this that y'all can think of?