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.
List of Imperial Diet participants (1792)
The Holy Roman Empire was a highly decentralized state for most of its history, composed of hundreds of smaller states, most of which operated with some degree of independent sovereignty. Although in the earlier part of the Middle Ages, under the Salian and Hohenstaufen emperors, it was relatively centralized, as time went on the Emperor lost more and more power to the Princes. The membership of the Imperial Diet in 1792, late in the Empire's history but before the beginning of the French Revolutionary Wars, gives some insight as to the composition of the Holy Roman Empire at that time.