In 1961 Bernstein had conducted at President John F. Kennedy's pre-inaugural gala, and he was an occasional guest in the White House. Years later he conducted at the funeral mass in 1968 for President Kennedy's brother Robert F. Kennedy, featuring the Adagietto from Mahler's 5th Symphony. Jackie Kennedy famously wrote to Bernstein after the event: "When your Mahler started to fill (but that is the wrong word — because it was more this sensitive trembling) the Cathedral today — I thought it the most beautiful music I had ever heard".