Flags of the Holy Roman Empire
In 1804, Napoleon Bonaparte declared the First French Empire. In response to this, Emperor Francis II of the Habsburg dynasty declared his personal domain to be the Austrian Empire and became Francis I of Austria. Taking the colours of the banner of the Holy Roman Emperor, the flag of the Austrian Empire was black and gold. Francis II was the last Holy Roman Emperor, with Napoleon forcing the empire's dissolution in 1806. After this point, these colours continued to be used as the flag of Austria until 1918.
German Question
On August 6, 1806, Habsburg Emperor Francis II had abdicated the throne of the Holy Roman Empire in the course of the Napoleonic Wars with France, thereby ending the loose Empire. Despite its later name affix "of the German Nation", the Holy Roman Empire had never been a nation state. Instead its rulers over the centuries had to cope with a continuous loss of authority to its constituent Imperial States. The disastrous Thirty Years' War proved especially fatal to the Holy Roman Emperor's authority, as the mightiest entities, the Austrian Habsburg Monarchy and Brandenburg-Prussia evolved into rivaling European absolute powers with territory reaching far beyond Imperial borders. The many small city-states splintered, meanwhile. In the 18th century the Holy Roman Empire consisted of over 1800 separate territories governed by distinct authorities.