From the time of Otto's reign the imperial office was based on the German kingship. The German king, elected by the German princes, automatically sought imperial coronation by the pope. After 1045 a king who was not yet crowned emperor was known as king of the Romans, a title that asserted his right to the imperial throne and implied that he was emperor-designate. Not every German king became emperor, however, because the popes, especially when elections to the kingships were disputed, often claimed that the selection of the emperor was their prerogative. Despite the fact that the German kingship and the imperial office were technically elective, they tended to become hereditary.
At times the electors, the German princes who approved the succession to the German kingship, exercised real authority in choosing the king, although papal confirmation was still necessary for accession to the imperial throne. In 1338 at the diets of Rhense and Frankfurt the German princes proclaimed the electors' right to choose the emperor without papal intervention. The Golden Bull of 1356 issued by Charles IV reaffirmed this and regulated the election procedure. Emperors continued to be crowned by the pope until after the coronation (1530) of Charles V. Thereafter, following the precedent (1508) of Maximilian I, they were crowned at Frankfurt. Several early emperors were also crowned king of Italy with the iron crown of the Lombards. After 1438 the imperial office was held, with one exception, by the house of Hapsburg.
The empire was justified by the claim that, just as the pope was the vicar of God on earth in spiritual matters, so the emperor was God's temporal vicar; hence he claimed to be the supreme temporal ruler of Christendom. Actually, the power of the emperor never equaled his pretensions. Although the emperors were accorded diplomatic precedence over other rulers, their suzerainty early ceased over France, S Italy, Denmark, Poland, and Hungary; and their control over England, Sweden, and Spain was never more than nominal. The authority of the emperors in Italy and Germany was sometimes nonexistent, sometimes real.
The territorial limits of the empire varied, but it generally included Germany, Austria, Bohemia and Moravia, parts of N Italy, present-day Belgium, and, until 1648, the Netherlands and Switzerland. Some countries (e.g., Hungary) were ruled by the emperor or imperial prince but were outside the empire, while others (e.g., Flanders, Pomerania, Schleswig, and Holstein) were part of the empire but were ruled by foreign princes who held their lands in fief from the emperor and took part in the imperial diet.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.