Ive been wondering what started the infighting between Houses Slytherin and Gryffindor...What do anda think?

Slytherin wanted to keep all the Hogwarts students pureblood. He didn't trust Muggleborns to keep the magic and the location a secret from their families. The other founders, especially Griffindor, disagreed about this.

Well, the answer is simple. Slytherin wanted all the students of Hogwarts to be Pure-Blood. That was just predajust (Can't spell). Gryffindor dissagreed with Slytherin's attitude. They argued for a while, then SLytherin eventually left. That's the story for today, Peeps!