That's a very good question. Supposedly the Spaniards brought some ingredients and the Peruvians took it from there, but of all the dishes I've had, Ceviche isn't quite like the rest of the Peruvian fare. I've not eaten a lot of that kind of food, but I have eaten quite a variety of Mexican cuisine and Ceviche is still different enough from the rest to make you wonder if there isn't some kind of Spanish influence there. Very good question. It looks like the historians are siding with the Peruvians on this one. :)