sentences:  After retiring as a professor of history from N.Y.U., he was a visiting professor at Cornell, Mt.Holyoke College, Smith College, the University of Illinois, and Georgetown University.He was the author of several books on European history, including "Europe and the French Imperium, 1799–1814," published in 1938; "Europe in Evolution," (1945) and "Europe and America Since 1492" (1954), as well as a biography of Georges Clemenceau, the French statesman, published in 1943.