Catechism of the Catholic Church §2421 — excerpt
The social doctrine of the Church developed in the nineteenth century when the Gospel encountered modern industrial society with its new structures for the production of consumer goods, its new concept of society, the state and authority, and its new forms of labor and ownership.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: CA 3