Columbia subject headings:
Catholic Church. Pope (1846-1878 : Pius IX). Syllabus errorum.
Church and state.
Papal States--Foreign relations.
Papal States.
Popes--Temporal power.
Harvard subject headings:
Church and state
Papal States--Foreign relations.
Papal States--History--1815-1870.
Pius IX, Pope, 1792-1878.
Popes--Temporal power
Roman question.
Princeton subject headings: