Pope Pius XI
Quadragesimo Anno §12
Quadragesimo Anno: On Reconstruction of the Social Order
12 The Apostolic voice did not thunder forth in vain. On the contrary, not only did the obedient children of the Church hearken to it with marveling admiration and hail it with the greatest applause, but many also who were wandering far from the truth, from the unity of the faith, and nearly all who since then either in private study or in enacting legislation have concerned themselves with the social and economic question.
Source: Quadragesimo Anno (Vatican.va)