Columbia subject headings:
Germany--History--Frederick I, 1152-1190.
Germany--History--Henry IV, 1056-1106.
Germany--History--Henry V, 1106-1125.
Germany--History--Konrad III, 1138-1152.
Germany--History--Lothair II, 1125-1137.
Harvard subject headings:
Germany--Kings and rulers
Germany--Politics and government--To 1517.
Holy Roman Empire--Kings and rulers
Princeton subject headings:
Germany--Kings and rulers.
Germany--Politics and government--To 1517.