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.
Kaiser
The Holy Roman Emperors (962–1806) called themselves "Kaiser", combining the imperial title with that of "King of the Romans" (assumed by the designated heir before the imperial coronation); they saw their rule as a continuation of that of the Roman Emperors and used the title derived from the title "Caesar" to reflect their supposed heritage.
In 1806 the Holy Roman Empire was dissolved, but the title of Kaiser was retained by the House of Habsburg, the head of which, beginning in 1804, bore the title of Emperor (Kaiser) of Austria. After 1438, the Habsburgs had provided most of Holy Roman Emperors, so they saw themselves as legitimate heirs to the title they adopted. Despite Habsburg ambitions however, the Austrian Empire could no longer claim to rule over most of Germany, although they did rule over large areas of lands inhabited by non-Germans in addition to Austria. There were four Kaisers of the Austrian Empire who all belonged to the Habsburg dynasty.