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.
History of the Roman Empire
After 395, the emperors in the Western Roman Empire were usually figureheads, while the actual rulers were military strongmen who took the title of "magister militum", "patrician" or both—Stilicho from 395 to 408, Constantius from about 411 to 421, Aëtius from 433 to 454 and Ricimer from about 457 to 472. The year 476 is generally accepted as the formal end of the Western Roman Empire. That year, Orestes, having stolen power from the emperor Julius Nepos the year before, refused the request of Germanic mercenaries in his service for lands in Italy. The dissatisfied mercenaries, including the Heruli, revolted. The revolt was led by the Germanic chieftain Odoacer. Odoacer and his men captured and executed Orestes; weeks later they captured Ravenna and deposed Orestes' usurper son, Romulus Augustus. This event has been traditionally considered the fall of the Roman Empire in the West. Odoacer quickly conquered the remaining provinces of Italy.