In 1909, Sigmund Freud, accompanied by his then disciple Carl Jung, made his one and only visit to the United States, to deliver a series of lectures on psychoanalysis at Clark University, in Worcester, Massachusetts. The honorary doctoral degree that Clark awarded him was the first public recognition Freud had ever received for his work. Despite the great success of this visit, Freud always spoke, in later years, as if some trauma had befallen him in the United States. He called Americans 'savages' and blamed his sojourn there for physical ailments that afflicted him well before 1909. Freud's biographers have long puzzled over this mystery, speculating whether some unknown event in America could have led to his otherwise inexplicable reaction.