Columbia subject headings:
Trier (Germany)--Church history.
Harvard subject headings:
Catholic Church. Diocese of Trier (Germany)--History.
Investiture.
Moselle River Valley--Church history.
Trier (Electorate)--History.
Trier Region (Germany)--Church history.
Princeton subject headings:
Investiture.
Moselle River Valley--Church history.
Trier Region (Germany)--Church history.