So the beginning is correct, the founders lived in peace but Slytherins didn't like muggle borns, Salzar left the school, but here's what they got wrong. Salzar didn't build the Chamber of Secrets. Slytherin the students did. You see they we sad that they're head was leaving they gave him a gift, they gave him a chamber that was home to a monster. (Rubie I am sorry if this insults you I ment no disrespect)