SOCIALISM, COMMUNISM, NIHILISM.
Quod Apostolici Muneris
December 28, 1878
THE STUDY OF SCHOLASTIC PHILOSOPHY.
Letter AEterni Patris
August 4, 1879
CHRISTIAN MARRIAGE.
Arcanum Divinae
February 10, 1880
FREEMASONRY.
Humanum Genus
April 20, 1884
THE CHRISTIAN CONSTITUTION OF STATES.
Immortale Dei
November 1, 1885
HUMAN LIBERTY.
Libertas Praestantissimum
June 20, 1888
THE RIGHT ORDERING OF CHRISTIAN LIFE.
Exeunte Jam Anno
December 25, 1888
THE CONDITION OF THE WORKING CLASSES.
Rerum Novarum
May 15, 1891