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.
Holy Roman Empire
A prospective Emperor had first to be elected King of the Romans (Latin: "Rex Romanorum"; German: "römischer König"). German kings had been elected since the 9th century; at that point they were chosen by the leaders of the five most important tribes (the Salian Franks of Lorraine, Ripuarian Franks of Franconia, Saxons, Bavarians, and Swabians). In the Holy Roman Empire, the main dukes and bishops of the kingdom elected the King of the Romans. In 1356, Emperor Charles IV issued the Golden Bull, which limited the electors to seven: the King of Bohemia, the Count Palatine of the Rhine, the Duke of Saxony, the Margrave of Brandenburg, and the archbishops of Cologne, Mainz, and Trier. During the Thirty Years' War, the Duke of Bavaria was given the right to vote as the eighth elector, and the Duke of Brunswick-Lüneburg (colloquially, Hanover) was granted a ninth electorate; additionally, the Napoleonic Wars resulted in several electorates being reallocated, but these new electors never voted before the Empire's dissolution. A candidate for election would be expected to offer concessions of land or money to the electors in order to secure their vote.