see: Imperial election
From the 13th century, the right to elect kings in the Holy Roman Empire was granted to a limited number of imperial princes, the so-called prince-electors. There are various theories over the emergence of their exclusive election right.[1]
The secular electoral seats were hereditary. However, spiritual electors (and other prince-(arch)bishops) were usually elected by the cathedral chapters as religious leaders, but simultaneously ruled as monarch (prince) of a territory of imperial immediacy (which usually comprised a part of their diocesan territory). Thus the prince-bishoprics were elective monarchies too. The same holds true for prince-abbeys, whose prince-abbesses or prince-abbots were elected by a college of clerics and imperially appointed as princely rulers in a pertaining territory.
Initially seven electors chose the "King of the Romans" as the Emperor's designated heir was known. The elected king then went on to be crowned by the Pope. The prince-electors were:
Later additions to the electoral council were: