Ernst I Duke of Saxe Gotha Altenburg
- Category : Notable-Famous-Royal-family
- Type : GE
- Profile : 5/1 - Heretical / Investigator
- Definition : Single
- Incarnation Cross : LAX Individualism 2
German nobleman, called "Ernest the Pious." He was Duke of Saxe-Gotha and Saxe-Altenburg, 1640-1675. The duchies were later merged into Saxe-Gotha-Altenburg. He was the ninth but sixth surviving son of John II, Duke of Saxe-Weimar, and Dorothea Maria of Anhalt. His mother was a granddaughter of Christoph, Duke of Württemberg, and great-granddaughter of Ulrich, Duke of Württemberg. He died at Schloss Friedenstein, Gotha, on 26 March 1675.