all know Hogwarts was founded over a thousand years ago by the four best wizards of its time. Godric Griffin-door, Rowina Raven-claw, Hilga hufflepuff, and Salazar Slitheren. Now three of founders coexisted quite peacefully, but one did not. Salazar Slitheren wished to be more selective of the students that were admitted to Hogwarts. He believed learning magic should be kept between all magic families in other words pure bloods. Unable to sway the others he decided to leave the school. This was the beginning of the chamber of secrets.