Why is the German flag black, red and gold?

The colours black, red and gold were originally used in the flag of the Holy Roman Empire of the German Nation (a black double-headed eagle with red claws and beak, on a gold background)

Another origin of the colours of the German flag lie in the 1813 wars of liberation against Napoleon. They are based on the colours of the uniforn of the Lützow Free Corps. The corps was made up mainly of students, who formed up to oppose the French occupation of Germany. The corps, commanded by Prussian Major Adolf von Lützow, was made up of people from all over Germany, all with different uniforms and the only way to create a unified uniform was to dye the clothing black. Gold coloured buttons were added to the uniform, along with red lapels and red stitching.

On June 17, 1817, seven students who had served in the Lützow Free Corps founded the fraternity of Jena (Burschenschaft zu Jena), with the motto Honour, Freedom, Fatherland, and chose black, red and gold as their fraternity colours.

On October 18, 1817, 500 fraternity students and some professors, attended the Wartburgfest, near Eisenach to demonstrate for freedom and a unified Germany, marching under a black, red and gold flag.

From May 27 to May 30, 1832, 30,000 people carried black, red and gold flags as they demonstrated for national and democratic goals at the Hambacher Fest.

In 1848 the German National Assembly officially declared the German flag to consist of three horizontal black, red and gold stripes.