Portrait of the American surgery pioneer Charles Horace Mayo (1865-1939). Together with his brother William James, he developed the St. Mary Hospital in Rochester, United States, which was founded in 1889 by his father William Worral Mayo. The hospital then evolved into the Mayo Clinic. In 1915, the two brothers founded the Mayo Foundation for medical education and research. Charles Horace Mayo introduced modern procedures in goiter surgery and neurosurgery.