Francis Willis (1718-1807) was a Lincoln-born clergyman whose true vocation was in medicine, in which he gained a degree from Oxford in 1759. He was particularly interested in the treatment of the mentally ill, marrying the harsh traditional treatments of the day with his own more gentle and unusual ones. He founded a rural sanatorium at his home at Greatford Hall, a few miles from Burghley, where his patients were encouraged to spend time in the fresh air and to do manual work on the estate farm. His alternative treatments proved highly successful and he came to be regarded as one of the foremost physicians of the day. His most famous patient was King George III, whom he twice successfully treated at the sanatorium and who is known to have been a frequent visitor to Dr. Willis thereafter. This beautiful pastel of the doctor was one of five portraits of him painted by John Russell R.A., one of the most illustrious portrait painters of the day.