Background on the Empire
On Christmas day in the year 800—more than three centuries after the abdication of the last Roman emperor—Charlemagne, the Carolingian king of the Franks, was crowned Emperor of the West by Pope Leo III. This act was seen as a revival, or transference, of the Roman empire (translatio imperii), prophesied to be the last of four earthly kingdoms preceding the Apocalypse. The imperial title, which asserted symbolic authority over all Christendom but had little concrete political significance, was passed to Charlemagne’s Carolingian successors. It was, however, the German emperor Otto I (r. 962–73) who, by military conquest and astute political policy, placed the territorial empire of Charlemagne under German rule and established in Central Europe the feudal state that would be called, by the thirteenth century, the Holy Roman Empire. From the time of Otto’s coronation until the official dissolution of the empire in 1806, the imperial title was held almost exclusively by German monarchs and, for nearly four centuries, by members of a single family.
Although most German kings attained imperial coronation, there were often several candidates for the throne. A body of princes, called electors, selected by majority vote both the German king and emperor; the crown, however, was only officially conferred by the pope, who occasionally claimed ultimate authority in the election. Over time, tensions mounted between the emperors and electors who, as one of the three representative groups in the Imperial Diet (or parliamentary body), kept the power of the monarch in check. The culmination of these tensions came with the Protestant Reformation of the sixteenth century: while the emperors adhered to Roman Catholicism, the electors generally supported the Reformation. It was, in fact, an elector—Frederick III (the Wise) of Saxony—who gave refuge to Martin Luther upon his excommunication.
The Habsburg Emperors
Rudolf I (died 1291), the first of nineteen emperors from the house of Habsburg, a noble family of Swiss origin, came to power in 1273. His defeat of King Otakar II of Bohemia (r. 1253–78) five years later gained significant territorial holdings for the Habsburgs in Austria, the cornerstone of their empire. By the sixteenth century, the imperial title was long regarded as hereditary, allowing the Habsburg dominion to expand dramatically over continental Europe not only through military conquest but also through carefully chosen marriage alliances.