German historian, born at Dusseldorf; was a pupil of Ranke's, and became professor of History at Munich and Bonn; he was a Liberal in politics; his great works are a "History of the Period of the French Revolution from 1789 to 1795, and then to 1800," in five volumes, and the "History of the Founding of the German Empire under William I.," in five volumes; he has also written a "History of the First Crusade" (1817-1895).