 Locke’s chief work while living at Lord Ashley’s residence, Exeter House, in 1668 was as Ashley’s physician. Locke used his medical training to organize a successful operation on Ashley. This was perhaps the most carefully documented operation in the 17th century. Locke consulted doctors across the country to determine what the best practices were for this operation and made cleanliness a priority. In doing so he saved his patron’s life and thus changed English history.