Pope John XXIII
Mater et Magistra §110
Mater et Magistra: On Christianity and Social Progress
110 This explains why social and political movements for the harmonizing of justice and freedom in society, though until recently opposed to the private ownership of productive goods, are today reconsidering their position in the light of a clearer understanding of social history, and are in fact now declaring themselves in favor of this right.
Source: Mater et Magistra (Vatican.va)