Hogwarts is founded by 4 great founder and the students were divided into each of their houses through sorting hat... who studies the students mind and decide which house to place them in Gryffindor, Hufflepuff, Raveclaw and Slytherin. These great founder's name were Gryffindor: - This house was founded by Godric Gryffindor and chose students who were brave and very well in studies and on their day to day duties. Huffelpuff: - This house was founded by Helga Huffelpuff. Ravenclaw: - This house was founded by Rowena Ravenclaw Slytherin: -  This house was founded by Salazar Slytherin...She did not agree about her selection of students... She felt that she should be more selective with her students so all those who were purebloods were sorted out in this house