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.
European wars of religion
The Holy Roman Empire, encompassing present-day Germany and surrounding territory, was the area most devastated by the wars of religion. The Empire was a fragmented collection of practically independent states with an elected Holy Roman Emperor as their titular ruler; after the 14th century, this position was usually held by a Habsburg. The Austrian House of Habsburg, who remained Catholic, was a major European power in its own right, ruling over some eight million subjects in present-day Germany, Austria, Bohemia and Hungary. The Empire also contained regional powers, such as Bavaria, the Electorate of Saxony, the Margraviate of Brandenburg, the Electorate of the Palatinate, the Landgraviate of Hesse, the Archbishopric of Trier, and Württemberg. A vast number of minor independent duchies, free imperial cities, abbeys, bishoprics, and small lordships of sovereign families rounded out the Empire.