Under pressure from Napoleon I both counties merged to form the Duchy of Nassau on 30 August 1806, under the joint rule of Frederick Augustus, and his younger cousin Frederick William.
Nassau | Nassau, Bahamas | Nassau County, New York | Grand Duchy of Lithuania | Duchy of Brabant | Duchy of Saxony | Duchy of Carinthia | Duchy of Burgundy | Duchy of Cornwall | Nassau County | Grand Duchy of Hesse | Grand Duchy of Mecklenburg-Schwerin | House of Orange-Nassau | Duchy of Parma | Chancellor of the Duchy of Lancaster | Order of Orange-Nassau | Duchy of Warsaw | Duchy of Prussia | Duchy of Jülich | Lorraine (duchy) | Grand Duchy of Baden | Duchy of Milan | Duchy of Mecklenburg-Schwerin | Duchy of Lancaster | Duchy of Holstein | Duchy of Savoy | Duchy of Nassau | Duchy of Limburg | Baldwin, Nassau County, New York | Hesse-Nassau |
At the time there were a family of Balloonists from London, Charles Green, who flew from London to Weilburg, Duchy of Nassau (Germany) in 1836 and by the time he retired in 1852, he had flown in a balloon more than 500 times.
The sovereigns of this house afterwards governed the Duchy of Nassau until 1866 and from 1890 the Grand Duchy of Luxembourg.
•
In 1816, Nassau-Usingen merged with Nassau-Weilburg to form the Duchy of Nassau.
After the death of Jacob Preuss in December 1826, Adamy was elected as a representative of the group of landowners in the electoral district of Dillenburg in the Second Chamber of the Estates of the Duchy of Nassau.
He was sent as representative of the Austrian imperial court to the principalities of Sachsen-Weimar-Eisenach, Nassau, Braunschweig, Oldenburg and Reuss.
Karl Wilhelm Diefenbach (February 21, 1851, Hadamar, Duchy of Nassau – December 15, 1913, Capri) was a German painter and social reformer.
By the German Mediatisation, the Lordship of Weingarten was incorporated into the Kingdom of Württemberg and the Nassau core territories into the Grand Duchy of Berg and the Duchy of Nassau.
Theodor Langhans (September 28, 1839 – October 22, 1915) was a German pathologist who was a native of Usingen, Duchy of Nassau.
1816: Wilhelm, Prince of Nassau-Weilburg and Duke of Nassau — Nassau-Weilburg merged into Duchy of Nassau