| Ernst I | |||||
|---|---|---|---|---|---|
 Photograph, c. 1870 | |||||
| Duke of Saxe-Altenburg | |||||
| Reign | 3 August 1853 – 7 February 1908 | ||||
| Predecessor | George | ||||
| Successor | Ernst II | ||||
| Born | 16 September 1826 Hildburghausen | ||||
| Died | 7 February 1908 (aged 81) Altenburg | ||||
| Spouse | |||||
| Issue | Marie, Princess Albert of Prussia | ||||
| |||||
| House | Wettin | ||||
| Father | Georg, Duke of Saxe-Altenburg | ||||
| Mother | Marie Luise of Mecklenburg-Schwerin | ||||
| Religion | Lutheranism | ||||
Ernst I, Duke of Saxe-Altenburg (German: Ernst I. Friedrich Paul Georg Nikolaus von Sachsen-Altenburg) (16 September 1826 in Hildburghausen – 7 February 1908 in Altenburg), was a duke of Saxe-Altenburg. He was the first son of Georg, Duke of Saxe-Altenburg and Marie Luise of Mecklenburg-Schwerin. In 1853 he succeeded his father as Duke of Saxe-Altenburg. He was of a retiring disposition and he took little active part in running the country. After a reign that lasted fifty five years, he died without a living direct male heir; because of this, he was succeeded by his nephew, Ernst.