Flag of Germany
When Heinrich XI, Prince Reuss of Greiz was appointed by Joseph II, Holy Roman Emperor to rule the then-new Principality of Reuss-Greiz on 12 May 1778, the flag adopted by the "Fürstentum Reuß-Greiz" was the first-ever appearance of the black-red-gold tricolour in its modern arrangement in any sovereign state within what today comprises Germany – the Reuss elder line that ruled the principality used a flag whose proportions were close to a "nearly square"-shape 4:5 hoist/fly ratio, instead of the modern German flag's 3:5 figure.
Flag of Germany
During the Napoleonic Wars, the German struggle against the occupying French forces was significantly symbolised by the colours of black, red, and gold, which became popular after their use in the uniforms of the Lützow Free Corps, a volunteer unit of the Prussian Army. This unit had uniforms in black with red facings and gold buttons. The colour choice had pragmatic origins, even though black-red-gold were the former colours used by the Holy Roman Empire. Members of the corps were required to supply their own clothing: in order to present a uniform appearance it was easiest to dye all clothes black. Gold-coloured buttons were widely available, and pennons used by the lancers in the unit were red and black. At the time, the colours represented: