Dorothea Lynde Dix (1802–1887) was a philanthropist and among the first American women to become active in social reform. Having been headmistress of her own school for girls in Boston from 1821 to 1836, in 1841 Dix toured Massachusetts state correctional institutions, where she was shocked to see deplorable treatment of the mentally ill. Thereafter Dix became an impassioned advocate for the mentally ill. Leading a drive to build hospitals for the specialized care of those afflicted with mental illnesses, Dix appealed to the consciences of legislators and philanthropists. She was successful in establishing mental hospitals throughout the United States, Canada, and Europe, many of which still bear her name. Dix’s campaign for humane treatment of the mentally ill transformed American attitudes and institutions in the two decades that led up to the Civil War (1861–65). During the war she acted as superintendent of the U.S. Army nurses. She also worked to improve prison conditions during her lifetime.