German nobility, as Ernst III the last sovereign duke of Saxe-Coburg-Saalfeld, and from 1826, the first sovereign duke of Saxe-Coburg and Gotha.
He was the eldest son of Francis, Duke of Saxe-Coburg-Saalfeld, and Countess Augusta of Reuss-Ebersdorf. His younger brother, Leopold Georg Christian Frederick, was later elected the first King of the Belgians.
When his father died in 1806, he succeeded in the duchy of Saxe-Coburg-Saalfeld as “Ernst III”, but could not take over the formal government of his lands, because the duchy was occupied by Napoleonic troops and was under French administration.
Ernst was a Prussian general and participated in military actions against Napoleon. He fought in the battles of Auerstedt (1806), Lützen and Leipzig (1813) and drew in 1814 into the French fortress of Mainz. After the defeat of Napoleon in the Battle of Waterloo, the Congress of Vienna on 9 June 1815 gave him an area of 8.25 square miles (21.4 km2) with 25,000 inhabitants around the capital St. Wendel. In 1819 this land received the name of Principality of Lichtenberg. He sold it to Prussia in 1834.
In Gotha on 3 July 1817 Ernest married Princess Luise of Saxe-Gotha-Altenburg. They had two children: Ernst II, Duke of Saxe-Coburg-Gotha and “Albert”, the husband of Queen Victoria and Prince Consort of the United Kingdom. His marriage was unhappy due to his own acts of infidelity. Ernst and Luise were separated in 1824 and were officially divorced on 31 March 1826.
The death in 1825 of the last duke of Saxe-Gotha-Altenburg, Luise’s uncle, resulted in a rearrangement of the Ernestine duchies. Ernst at the time was in the process of divorcing Luise, and because of this the other branches objected to him receiving Gotha. They reached a compromise on 12 November 1826: Ernst received Gotha and ceded Saalfeld to Saxe-Meiningen. He subsequently became “Ernst I, Duke of Saxe-Coburg and Gotha”.
In Coburg on 23 December 1832, Ernst married for a second time to his niece Duchess Marie of Württemberg, the daughter of his sister Antoinette. They had no children. This marriage made Marie both Prince Albert’s cousin and his stepmother.
Ernst also had three illegitimate children. He is the patrilineal ancestor of, inter alios, both the Duke of Gloucester and Duke of Kent, as well as being the great-great-great-grandfather of Queen Elizabeth II. He died on 29 January 1844.
Link to Wikipedia biography