31 It can certainly be claimed that the lay cooperation which we today call Catholic Action, has existed since the foundation of the Church. Indeed the Apostles and other preachers of the Gospel received no little help from it and the Christian religion thereby made great advances. In this respect Apollo, Lydia, Aquila, Priscilla and Philemon are mentioned by the Apostle of the Gentiles. We have also these words of his to the Philippians: "Yes, and I ask thee, who sharest the yoke so loyally, to take part with them; they have worked for the Gospel at my side, as much as Clement and those other fellowlaborers of mine, whose names are recorded in the book of life."
Source: Evangelii Praecones (Vatican.va)