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
The 1815–16 Congress of Vienna led to the creation of the German Confederation, a loose union of all remaining German states after the Napoleonic Wars. The Confederation was created as a replacement for the now-extinct Holy Roman Empire, with Francis I of Austria—the last Holy Roman Emperor—as its president. The confederation did not have a flag of its own, although the black-red-gold tricolour is sometimes mistakenly attributed to it.
Upon returning from the war, veterans of the Lützow Free Corps founded the fraternity in Jena in June 1815. The Jena eventually adopted a flag with three equal horizontal bands of red, black, and red, with gold trim and a golden oak branch across the black band, following the colours of the uniforms of the Free Corps. Since the students who served in the Lützow Free Corps came from various German states, the idea of a unified German state began to gain momentum within the and similar that were subsequently formed throughout the Confederation. On 18 October 1817, the fourth anniversary of the Battle of Leipzig, hundreds of fraternity members and academics from across the Confederation states met in Wartburg in Saxe-Weimar-Eisenach (in modern Thuringia), calling for a free and unified German nation.