Leo XIII returns to the subject of social inequality in the encyclical Rerum Novarum, of May 15, 1891:
Let it, then, be taken as granted, in the first place, that the condition of things human must be endured, for it is impossible to reduce civil society to one dead level. Socialists may in that intent do their utmost, but all striving against nature is in vain. There naturally exist among mankind manifold differences of the most important kind; people differ in capacity, skill, health, strength; and unequal fortune is a necessary result of unequal condition.
Such inequality is far from being disadvantageous either to individuals or to the community. Social and public life can only be maintained by means of various kinds of capacity for business and the playing of many parts; and each man, as a rule, chooses the part which suits his own particular domestic condition.
(Rev. John J. Wynne, S.J., ed. The Great Encyclical Letters of Pope Leo XIII [New York: Benziger Brothers, 1903], p. 217).
Plinio Corrêa de Oliveira, Nobility and Analogous Traditional Elites in the Allocutions of Pius XII: A Theme Illuminating American Social History (York, Penn.: The American Society for the Defense of Tradition, Family, and Property, 1993), Documents V, pp. 479-480.