Columbia subject headings:
Harvard subject headings:
Germany--History--Henry IV, 1056-1106--Congresses.
Henry IV, Holy Roman Emperor, 1050-1106--Congresses.
Holy Roman Empire--History--Henry IV, 1056-1106--Congresses.
Holy Roman Empire--Kings and rulers--Biography--Congresses.
Princeton subject headings:
Germany--History--Henry IV, 1056-1106--Congresses.
Henry IV, Holy Roman Emperor, 1050-1106--Congresses.
Holy Roman Empire--History--Henry IV, 1056-1106--Congresses.
Holy Roman Empire--Kings and rulers--Biography--Congresses.