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.
Reichskriegsflagge
The German war flag, which was slightly changed two times during the Wilhelmine Period (see gallery below), was in common use in World War I. It continued to have Prussia's national colours of black and white, the eagle of Prussia, the Nordic cross, with the German imperial black-white red tricolour in the upper canton with an Iron Cross. In 1919, the flags of Imperial Germany were scrapped and replaced by those of the Weimar Republic: a black-red-gold tricolour.