In 1963 Richard Feynman was invited to give the 1964 Messenger Lectures at Cornell University, an annual tradition since 1924, when Hiram Messenger gifted Cornell with "a fund to provide a course of lectures on the Evolution of Civilization for the special purpose of raising the moral standard of our political, business, and social life", to be "delivered by the ablest non-resident lecturer or lecturers obtainable".
Feynman had been a physics professor at Cornell from 1945 to 1950, during which time he did the work for which he was awarded a Nobel Prize in 1965. While at Cornell Feynman became well-known in the physics community for his innovations in quantum electrodynamics and idosyncratic style. He was at Caltech in 1963, when he was invited to become the 41st Messenger Lecturer, by which time he had become known to a much wider audience through his recently published book, Volume I of The Feynman Lectures on Physics.
https://www.feynmanlectures.caltech.edu/messenger.html