60 And in the discourse which We gave in 1944 to the directors of the Pontifical Missionary Society, We said: "The herald of the Gospel and messenger of Christ is an apostle. His office does not demand that he transplant European civilization and culture, and no other, to foreign soil, there to take root and propagate itself. His task in dealing with these peoples, who sometimes boast of a very old and highly developed culture of their own, is to teach and form them so that they are ready to accept willingly and in a practical manner the principles of Christian life and morality; principles, I might add, that fit into any culture, provided it be good and sound, and which give that culture greater force in safeguarding human dignity and in gaining human happiness. Catholic inhabitants of missionary countries, although they are first of all citizens of the Kingdom of God and members of His great family, do not for all that cease to be citizens of their earthly fatherland."
Source: Evangelii Praecones (Vatican.va)