The Prince-electors of the Holy Roman Empire were the members of the electoral college of the Holy Roman Empire, having the function of electing the Roman king or, from the middle of the 16th century onwards, directly the Holy Roman Emperor.
The heir-apparent to a prince-elector was known as an electoral prince. The dignity of Elector was extremely prestigious and second only to King or Emperor.
The Holy Roman Empire was in theory an elective monarchy, but from the 15th century onwards the electors often merely formalised what was a dynastic succession within the Austrian House of Habsburg, with the title usually passing to the eldest surviving son of the deceased Emperor. Despite this, the office was not legally hereditary, and the heir could not title himself Emperor without having been personally elected.
Formally they elected a King of the Romans, who was elected in Germany but became Holy Roman Emperor only when crowned by the pope. Charles V was the last to be a crowned Emperor; his successors were all Emperors by election only.
Electors were among the princes of the Empire, but they had privileges in addition to their electoral ones which were not allowed their non-electoral brethren. Though in principle not a title of nobility – and thus held in addition to such feudal titles as Duke, Margrave, or Count Palatine – the dignity of Elector was extremely prestigious.
At least from the thirteenth century, there were seven electors, three spiritual: the Archbishop of Mainz, the Archbishop of Trier, and the Archbishop of Cologne, and four lay: the King of Bohemia, the Count Palatine of the Rhine, the Duke of Saxony, and the Margrave of Brandenburg; these last three were also known as the Elector Palatine, the Elector of Saxony, and the Elector of Brandenburg, respectively.
Only six of the electors, however, had the right to sit at ordinary meetings: The King of Bohemia, who was in fact not a prince of the Empire but a neighbouring and independent monarch, might vote at an imperial election, but was allowed on no other occasion to meddle in the affairs of the Empire.
Other electors were added in the seventeenth century and include the Duke of Bavaria – referred to as the Elector of Bavaria replacing the Count Palatine of the Rhine, who was of the same family but had lost his title temporarily during the Thirty Years’ War – and the Duke of Brunswick-Lüneburg – the Elector of Hanover. The office in time held by three Hanoverian kings of Great Britain, George I, George II, and George III, until the institution was abolished in 1806 under Napoleon Bonaparte and the Elector became the King of Hanover after regaining his lands following Napoleon’s defeat in 1814.
Several new electors were created during the reorganization of the Empire in 1803, but these never participated in an election.
On August 6, 1806, pressed both by Napoleon and by several German princes – including some Electors – the last Holy Roman emperor, Emperor Francis II, by edict dissolved the Empire.
After or just before the dissolution, the Electors of Bavaria, Württemberg, Saxony, and, eventually, of Hanover each took the title of king of his former electorate, while the King of Prussia extended his royal title to cover his erstwhile Electorate of Brandenburg as well as the lands he held as king outside the imperial border. The Electors of Regensburg who had succeeded to the Mainz vote, Würzburg who had succeeded to the Salzburg vote, and Baden which was a new electorate became grand dukes. The Elector of Hesse and Landgrave of Hesse-Kassel chose to retain the defunct electoral title until the state was annexed by Prussia, sixty years later.