city hall, was built in 1609 and 1610. No older buildings are preserved due to two fires in 1547 and 1561.
In 1648, at the end of the devastating 30 years war, chronicles tell that Wiesbaden had barely 40 residents left.
In 1659, the Countship of Nassau-Weilburg was divided again. Wiesbaden became part of the Countship of Nassau-Usingen. In 1744, the seat of Nassau-Usingen was moved to Biebrich.
In 1771, the Count of Nassau-Usingen granting a concession for gambling in Wiesbaden. In 1810, the Wiesbaden Casino (German: Spielbank) was opened in the old Kurhaus. Gambling would later be outlawed by Prussian authorities in 1872.
As a result of Napoleon's victory over Austria in the Battle of Austerlitz in 1805, the Holy Roman Empire was dissolved. On July 12, 1806, 16 states in present-day Germany, including the remaining Countships of Nassau-Usingen and Nassau-Weilburg, formally left the Holy Roman Empire and joined together in the Confederation of the Rhine. Napoleon was its "protector." Under pressure from Napoleon, both countships merged to form the Duchy of Nassau on August 30, 1806.
At the 1815 Congress of Vienna, the Duchy of Nassau joined the German Confederation. The capital of Nassau was moved from Weilburg to Wiesbaden, and the city became the ducal residence. Building activity started in order to give the city a magnificent appearance. Most of the historical center of Wiesbaden dates back to this time.
In the Revolutions of 1848, 30,000 citizens of Nassau assembled in Wiesbaden on March 4. They demanded a constitution from the Duke, which they received.
In the Austro-Prussian War of 1866, Nassau took Austria's side. This decision led to the end of the duchy. After the Austrian defeat Nassau was annexed by Prussia and became part of the Prussian province of Hesse-Nassau. The deposed duke Adolph of Nassau in 1890 became the Grand Duke of Luxembourg (see House of Nassau).
In the subsequent period,
