Frédéric-Guillaume (Friedrich Wilhelm) (1771-June 16, 1815) known as the "black duke", is the son and successor of Duke Charles Guillaume Ferdinand of Brunswick, author of the Brunswick Manifesto. In France, he is also known as a Duke of Oels. He belongs to the family of the Guelphs (Welfen) who have ruled today's Lower Saxony since the Middle Ages. In 1806 he was crown prince of his family in the Duchy of Brunswick-Lüneburg, part of Wolfenbüttel. His father was the most renowned general in all of Europe, but, alas, he had lost two important battles:that of Valmy and, what was worse, that of Jena.
After the victory of Jena, Napoleon was determined to transform this principality into a simple department of his future kingdom of Westphalia. But the loss of his inherited duchy at the Treaty of Tilsit in 1806 made him one of the most fierce opponents of Napoleonic domination over Germany. With his "private" army, his body of partisans called "the black cadre" (because of the color of their uniforms), he took part in the war of 1809 alongside rebellious Austria. The corps included an infantry regiment, a squadron of hussars and a battery. The Duke knew well that it was necessary to be among the combatants to count at a future peace congress!
After Austria's defeat at the Battle of Wagram that same year, it was therefore resolved to leave for England, crossing Bohemia and northwestern Germany, despite the enemy troops. After taking Halberstadt he fought the outnumbered Westphalians who were trying to stop him at Oelper near Brunswick. There he remained victorious against the French general Reubell. Then he embarked and his army at Elsfleth (near the town of Oldenburg) on American ships.
In the meantime, moreover, on several occasions, he secretly visited his duchy, which had become Westphalian, which helped to sustain his continued popularity.
Incorporated into the British Army, his military corps fought with great success in Spain with Wellington. He returned to Brunswick in 1813, where he raised fresh troops. He was killed at the Battle of Quatre-Bras, near Waterloo.
As I said, it remains very popular. Today, a local beer bears his name "Schwarzer Herzog".
He left two sons with his wife Marie de Bade:
1. Charles (Duke Charles II of Brunswick) and
2. William (Duke William VIII of Brunswick).
Monuments in his memory:
The "Black Duke“, monument erected on November 10, 1874, sculptor Georg Ferdinand Howaldt. From May 2007 , again in front of the rebuilt ducal palace in Brunswick.
memorial at Oelper (near Brunswick) in memory of said battle
memorial at Brunswick (Porte St. Pierre), where the Duke bivouacked during the campaign of 1809
memorial in Burgdorf (Lower Saxony), where the duke bivouacked during this same campaign
memorial at Syke (Lower Saxony), where the duke also bivouacked