The history of the world of pokemon has been admittedly relatively peaceful. However, I must admit that we have still seen our fair share of wars in which pokemon were indeed involved. But I suspect that holds true for many creatures that coexist with human beings.

((ooc: Elephants used by Hannibal, Horse cavalry used by... just about everyone, Dogs used to sniff out bombs, the kind of things Lance wouldn't necessarily know about Earth history.))