Ernst II Duke of Saxe Altenburg
- Category : 1871-births
- Type : GE
- Profile : 3/5 - Martyr / Heretic
- Definition : Triple Split
- Incarnation Cross : RAX Planning 3
German monarch, the last reigning duke of Saxe-Altenburg, and the last survivor of the German princes who had reigned until 1918.
He was the fourth child but only son of Prince Moritz, the youngest son of Georg, Duke of Saxe-Altenburg and Princess Augusta of Saxe-Meiningen.
The death of his father on 13 May 1907 made him first in the line of succession to the duchy of Saxe-Altenburg. He inherited the dukedom when his uncle and namesake Ernst I, died without surviving male issue, on the 7 February 1908.
During World War I, Ernst refused all honorary appointments at the Kaiser's headquarters (which would have been considerably safer than other areas). He renounced his rank as General, entered the service as a Colonel, and distinguished himself at the Battle of Péronne. By the end of the war, he was a commander of a division.
He was forced to abdicate the government of the duchy on 13 November 1918, and spent the rest of his life like a private citizen.
On 27 February 1898 in Bückeburg Ernst married his first wife, Princess Adelaide of Schaumburg-Lippe, a granddaughter of Georg Wilhelm, Prince of Schaumburg-Lippe. They had four children.
On 15 July 1934 Ernst married his second wife Maria Triebel, who had been his companion for many years, at his home, Schloss Froehliche Wiederkunft ("Palace of Happy Returning") at Wolfersdorf. This was a morganatic marriage, and she received only the title of "Baroness Reiseneck". They had no children.
In March 1954, with the death of Karl Eduard, Duke of Saxe-Coburg and Gotha, he became the last survivor of the German princes who had reigned until 1918. One year later, on 22 March 1955, he died at his Schloß.