Columbia subject headings:
Alexander III, Pope, -1181.
Catholic Church--Foreign relations--Holy Roman Empire.
Catholic Church--Italy--History.
Holy Roman Empire--Foreign relations--Catholic Church.
Victor IV, Antipope, -1164.
Harvard subject headings:
Alexander III, Pope, -1181
Catholic Church--Foreign relations--Holy Roman Empire.
Catholic Church--Italy--History.
Christianity and politics--Holy Roman Empire--History.
Church and state--Holy Roman Empire--History.
Frederick I, Holy Roman Emperor, approximately 1123-1190.
Holy Roman Empire--Foreign relations--Catholic Church.
Italy--Church history--12th century.
Papacy--History--To 1309
Victor IV, Antipope, -1164.
Victor IV, Antipope, 1159-1164.
Princeton subject headings: