Horace Mann was a reformer from the mid-1800s. He is best known for his efforts towards improving the state of public education in the United States.
During the 1830s and 1840s, there were a number of reform movements going on in the United States. There was a growing middle class that believed in the somewhat progressive idea that people could more or less perfect their society. Mann started his work in areas other than education. He worked on improving mental hospitals, just as Dorothea Dix did.
However, it was later that Mann took up the cause that he became famous for. He became the most important education reformer in America in those days. Mann was responsible for the creation of normal schools for training teachers and extending educational opportunities to many more children in Massachusetts. As the link below says,
Mann, more than any other single person, is responsible for bringing Massachusetts, and in turn the nation, to acknowledge the importance of providing public education for all mentally competent citizens.