The Mayo Clinic is an American medical practice and research centre in Rochester, Minnesota. The Clinic evolved out of the late nineteenth-century surgical partnership of physicians William James Mayo (1861-1939) and Charles Horace Mayo (1865-1939), both of whom helped to found St Mary’s Hospital, Rochester in 1899 with their father, William Worrall Mayo (1819-1911). The Clinic’s educational and research activities expanded significantly in the early twentieth-century following the Mayo brothers’ establishment of the Mayo Foundation for Medical Education and Research at the University of Minnesota in 1915.