One of the original founders of Hogwarts “over a thousand years ago.” Salazar Slytherin believed that only pure-blood witches and wizards should be allowed to attend Hogwarts. He got into an argument with Godric Gryffindor about this and eventually left the school. There was a legend that Slytherin built a secret chamber somewhere in Hogwarts that only his true heir would be able to open. This chamber, called the Chamber of Secrets, contained a monster that would finish his “noble purpose” of killing all the Muggle-born students at Hogwarts (Pm). According to legend, Slytherin reconciled with the other Founders later in life and came back to Hogwarts castle to die (JKR-W3). (The Harry Potter Lexicon)
Hearseeno 