ODragon: BruceS: The reason the Leon didn't yield is anything is because of spelling. The spelling in the the category is Ponce de León with the accent mark.
Sounds like Leon (no accent) would make a good keyword.
Yes. Skimming through Wikipedia, I'd say keywords (limit of ten, last I checked) for that category should be:
leon
spain
florida
columbus
explorer
san
santiago
cristobal
maria
caribbean