Jascha Heifetz (1901–1987) was a Lithuanian-born American violinist, among the most celebrated instrumentalists of his era. He is not the author of this joke — but he is the first person the joke is known to have been attached to, in Bennett Cerf’s syndicated humor column of 9 November 1955 — the earliest naming in Popik’s chronology — which offered the story as hearsay rather than fact: “Rumor is that a pedestrian in Manhattan stopped Jascha Heifetz…” Cerf reprinted it in his 1956 anthology The Life of the Party, and from there the gag travelled. Arthur Rubinstein was substituted for Heifetz only later, with no source behind the swap.