Treitschke, Heinrich von (1834–1896), a German historian. He was a fervent and articulate advocate of German nationalism, imperialism, and unification under Prussian leadership. Treitschke's writings were extremely influential in Germany prior to World War I. His major work was History of Germany in the Nineteenth Century (5 volumes, 1879–94), a vivid and detailed narrative of German national development.

Treitschke was born in Dresden. After receiving a doctorate from the University of Leipzig, he taught there, 1858–63, and at Freiburg, 1865–66. He became professor of history at the University of Kiel in 1866, at Heidelberg in 1867, and at Berlin in 1874. In 1886 Treitschke succeeded Leopold von Ranke as official historian of the state of Prussia. He also served in the Reichstag (lower house of the German parliament), 1871–88.