John Fitzgerald Kennedy (May 29, 1917 – November 22, 1963), often referred to by his initials JFK or by his nickname Jack, was an American politician who served as the 35th president of the United States from January 1961 until his assassination in November 1963. That fall, he enrolled at the Stanford Graduate School of Business and audited classes there. In early 1941, Kennedy left and helped his father write a memoir of his time as an American ambassador. He then traveled throughout South America; his itinerary included Colombia, Ecuador and Peru. Kennedy was hospitalized at the Chelsea Naval Hospital in Chelsea, Massachusetts from May to December 1944. He then traveled throughout South America; his itinerary included Colombia, Ecuador and Peru. Kennedy was hospitalized at the Chelsea Naval Hospital in Chelsea, Massachusetts from May to December 1944. On June 12, he was presented the Navy and Marine Corps Medal for his heroic actions on August 1–2, 1943, and the Purple Heart Medal for his back injury while on PT-109.