Over a thousand years ago, four witches and wizards set out on a mission. Their goal: to educate the wizard children of Britain. Thus Hogwarts School of Witchcraft and Wizadry was born. Its founders were Godric Gryffindor, Helga Hufflepuff, Rowena Ravenclaw, and Salazar Slytherin.
Each of these four picked students from all over the countryside to attend Hogwarts. Gryffindor valued students with daring and chivalry, Hufflepuff liked ones who were hard working and just, Ravenclaw prefered people with wit and learning, and Slytherin picked ones with ambition and cunning.
Hogwarts became a world renowned school of magic. But, as the school progressed, a large argument broke out among the teachers. Slytherin was disappointed with Gryffindor's pick of students. Gryffindor believed that anyone with magical talent should be allowed into Hogwarts, while Slytherin wouldn't let anyone but pure-bloods into his section of the school. A rift grew betweeen these two figures. Finally, Slytherin, in a rage, left the school. However a rumor stayed that became legend.
Slytherin was supposed of building a chamber in the school, a chamber which none of the other Founders knew about. Slytherin said that when his true heir arrived at Hogwarts, he would be able to open the Chamber of Secrets, and release the horror within to cleanse the school of all which Slytherin deemed unworthy.