http://www.biography.com/people/horace-mann-9397522 http://www.biography.com/people/horace-mann-9397522 Mann Horace Mann https://www.biography.com/people/horace-mann-9397522 https://www.biography.com/people/horace-mann-9397522 Horace Mann Horace Mann Horace Mann Horace Mann Horace Mann Horace Mann Horace Mann Six Principles of Education http://www.biography.com/people/horace-mann-9397522 Horace Mann