Semmelweis is lauded today as the great pioneer of antiseptic medicine -- but it was very different in his own day. His discovery of the cause of childbed (puerperal) fever, and that the rate of maternal death in the hospital could be drastically reduced by hand-washing, was considered heresy by the medical establishment, which refused to believe that doctors were contaminating the patients. In 1861, he published his principal work, Die Ätiologie, der Begriff und die Prophylaxis des Kindbettfiebers (The Etiology, Concept, and Prophylaxis of Childbed Fever). Prominent obstetricians and medical societies rejected it. He addressed several open letters to professors of medicine in other countries, but to little effect. In 1865, he suffered a breakdown and was taken to a Viennese mental hospital, where he died.