Duke Ernst August of Saxe-Weimar (1613-1683) was a German nobleman and a member of the House of Wettin. He ruled the duchy of Saxe-Weimar during a tumultuous period marked by the Thirty Years' War. His leadership was characterized by efforts to rebuild and stabilize his territory after the devastation of the war. Ernst August was known for his patronage of the arts and education, contributing to the cultural development of Weimar. He supported the establishment of the University of Jena, which became an important center for learning in Germany. His reign helped lay the groundwork for the future prosperity of the region.