Emperor
The first Austrian Emperor was the last Holy Roman Emperor Francis II. In the face of aggressions by Napoleon, Francis feared for the future of the Holy Roman Empire. He wished to maintain his and his family's Imperial status in the event that the Holy Roman Empire should be dissolved, as it indeed was in 1806 when an Austrian-led army suffered a humiliating defeat at the Battle of Austerlitz. After which, the victorious Napoleon proceeded to dismantle the old "Reich" by severing a good portion from the empire and turning it into a separate Confederation of the Rhine. With the size of his imperial realm significantly reduced, Francis II, "Holy Roman Emperor" became Francis I, "Emperor of Austria". The new imperial title may have sounded less prestigious than the old one, but Francis' dynasty continued to rule from Austria and a Habsburg monarch was still an emperor ("Kaiser"), and not just merely a king ("König"), in name.
Fall of Ravenna
The Fall of Ravenna, capital of the Western Roman Empire, occurred in early September 476 after a minor confrontation between the Heruli under their King Odoacer and the remnants of the Western Roman Army in Italy. The Roman Empire had been in relative decline since the beginning of the barbarian invasions and Rome, the symbolical heart and largest city of the Western Empire, was sacked in 410 by the Visigoths and in 455 by the Vandals. By 476 the Roman Emperor was little more than a warlord having very little de facto control of any territory outside of Italy. The last Roman emperor, Romulus Augustulus, was not even recognized as a legitimate ruler outside of Italy; the Eastern Roman Empire recognized Julius Nepos as the true Western Roman Emperor.