In 1806, the city was captured by the French during the Napoleonic Wars and became part of the short-lived Napoleonic Kingdom of Westphalia in 1807.
The exiled duke Frederick William raised a volunteer corps, the Black Brunswickers, who fought the French in several battles.

After the Congress of Vienna in 1815, Braunschweig was made capital of the reestablished independent Duchy of Brunswick, later a constituent state of the German Empire from 1871.
In the aftermath of the July Revolution in 1830, in Brunswick duke Charles II was forced to abdicate.
His absolutist governing style had previously alienated the nobility and bourgeoisie, while the lower classes were disaffected by the bad economic situation.
During the night of 7–8 September 1830, the ducal palace in Braunschweig was stormed by an angry mob, set on fire, and destroyed completely.
Charles was succeeded by his brother William VIII.
During William's reign, liberal reforms were made and Brunswick's parliament was strengthened.

During the 19th century, industrialisation caused a rapid growth of population in the city, eventually causing Braunschweig to be for the first time significantly enlarged beyond its medieval fortifications and the River Oker.
On 1 December 1838, the first section of the Brunswick–Bad Harzburg railway line connecting Braunschweig and Wolfenbüttel opened as the first railway line in Northern Germany, operated by the Duchy of Brunswick State Railway.
In 1806, the city was captured by the French during the Napoleonic Wars and became part of the short-lived Napoleonic Kingdom of Westphalia in 1807. The exiled duke Frederick William raised a volunteer corps, the Black Brunswickers, who fought the French in several battles.
After the Congress of Vienna in 1815, Braunschweig was made capital of the reestablished independent Duchy of Brunswick, later a constituent state of the German Empire from 1871. In the aftermath of the July Revolution in 1830, in Brunswick duke Charles II was forced to abdicate. His absolutist governing style had previously alienated the nobility and bourgeoisie, while the lower classes were disaffected by the bad economic situation. During the night of 7–8 September 1830, the ducal palace in Braunschweig was stormed by an angry mob, set on fire, and destroyed completely. Charles was succeeded by his brother William VIII. During William's reign, liberal reforms were made and Brunswick's parliament was strengthened.
During the 19th century, industrialisation caused a rapid growth of population in the city, eventually causing Braunschweig to be for the first time significantly enlarged beyond its medieval fortifications and the River Oker. On 1 December 1838, the first section of the Brunswick–Bad Harzburg railway line connecting Braunschweig and Wolfenbüttel opened as the first railway line in Northern Germany, operated by the Duchy of Brunswick State Railway.
Braunschweig