Henry Morgenthau, Sr. (April 26, 1856 – November 25, 1946)was a German-born American businessman and United States ambassador. He is most known by his job as ambassador to the Ottoman Empire during World War I. He was father of the politician, Henry Morgenthau, Jr. and the grandfather of Robert M. Morgenthau, the current District Attorney of New York County, and historian Barbara Tuchman.