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.
Pax Romana
The Pax Romana (Latin for "Roman Peace") was a long period of relative peace and stability experienced by the Roman Empire. It is traditionally dated as commencing from the accession of Caesar Augustus, founder of the Roman principate, in 27 BCE and concluding in 180 CE with the death of Marcus Aurelius, the last of the "good emperors". Since it was inaugurated by Augustus with the end of the Final War of the Roman Republic, it is sometimes called the Pax Augusta. During this period of approximately 206 years, the Roman empire achieved its greatest territorial extent and its population reached a maximum of up to 70 million people – a third of the world’s population. According to Cassius Dio, the dictatorial reign of Commodus, later followed by the Year of the Five Emperors and the crisis of the third century, marked the descent "from a kingdom of gold to one of iron and rust".