Columbia subject headings:
Holy Roman Empire--History--843-1273.
Kings and rulers, Medieval--Succession.
Kings and rulers, Medieval.
Harvard subject headings:
Holy Roman Empire--Kings and rulers--Succession.
Konrad III, King of the Romans, 1093-1152.
Princeton subject headings:
Holy Roman Empire--History--843-1273.
Kings and rulers, Medieval--Succession.
Kings and rulers, Medieval.