Johann Adolf II, Duke of Saxe-Weissenfels (Weissenfels, 4 September 1685 – Leipzig, 16 May 1746), was the last duke of Saxe-Weissenfels-Querfurt and a member of the House of Wettin. He was also a commander in the Saxon army.
Johann Adolf was the youngest of the twenty children of Johann Adolf I, Duke of Saxe-Weissenfels, and Johanna Magdalene of Saxe-Altenburg. His mother died five months after his birth, on 22 January 1686.
In the War of the Polish Succession, Johann Adolf led Saxon troops into Poland (October 1733). For the next 3 years, the Saxon army remained mainly in southern Poland, until the coronation of the Elector Frederick August II of Saxony as King of Poland after the defeat of the rival candidate for the Polish throne, Stanisław Leszczyński. The same year, Johann Adolf inherited Saxe-Weissenfels when his brother Christian died without children.
During the Second Silesian War, Prussian troops crossed the Saxon border, and Saxony and Austria agreed to proceed together against Prussia. Saxon troops planned to cut off the Prussians in northern Silesia, while Austrian troops would advance from the south. But in June 1745, they were defeated at the Battle of Hohenfriedberg. Johann Adolf planned a new offensive campaign in September 1745, but he changed his mind two weeks later. Because of this, he was replaced as commander-in-chief by Count Frederick August Rutowski, an illegitimate half-brother of the King-Elector.
After the Battle of Kesselsdorf, the Elector removed his half-brother Rutowski as commander-in-chief and reinstated Johann Adolf, who began his duties as commander on 1 December 1745. Additionally, he was appointed chief of the Saxon government during the absence of the Elector and the Minister Heinrich of Brühl.
Johann Adolf retreated with the Saxon troops to Bohemia. Five months later, he suffered a heart attack and died at age sixty-one.
In Eisenach on 9 May 1721, Johann Adolf married Johannette Antoinette Juliane of Saxe-Eisenach. They had one son:
In Altenburg on 27 November 1734, Johann Adolf married for a second time to Fredericka of Saxe-Gotha. They had five children:
He was the last member of the line of Saxe-Weissenfels-Querfurt. After his death without surviving male issue, his lands passed to the Electorate of Saxony, from which they had been extracted in 1657 under the terms of the will of John George I, Elector of Saxony
| Preceded by Christian |
Duke of Saxe-Weissenfels 1736 – 1746 |
Succeeded by Territories of the Duchy of Saxe-Weissenfels returned to the Electorate of Saxony |