It would be worth it to unpack the historical development of Christian culture as Wilken traces it.
The starting point is the way that Christ came into the world: «But Christ entered history as a community, a society, not simply as a message, and the form the community’s life takes is Christ within society.»
This society, the Church, started by embracing the good around them, and by discovering a new significance in the symbols already in use around them.
«In buying and displaying objects such as lamps or ring or seals Christians created the first Christian art (of which we have knowledge), but what the symbols represented lay in the eyes of the beholder, not in the object. As far as Roman society was concerned Christianity was invisible.»
My mother gave me a metal decor cross to me for my birthday. This cross was bought and sold as an object with no memory of its significance except as a conventional form. But my mother recognized it for what it means and gave it to me. A similar example would be to listen to the human cry of pop songs with the ear of Christ.
Then Christians begin something new. They bury their dead in catacombs, hallowing out a place of memory that is out of the way and yet public.
«Significantly Christian culture first takes material shape in connection with caring for and remembering the dead. Memory, especially of the faithful departed, is a defining mark of Christian identity.»
Memory is the key word here, but it is not only the memory of the dead, of the saints that we remain in communion with - it is above all the memory of Christ's presence, his crucifixion and resurrection. The memory of the saints is the experience of Christ's resurrection in His people. Christ present keeps the saints present with us.
In time, the universal (catholic, ecumenical) dimension of the Christian proposal becomes evident. Christendom becomes the expression of a society transformed by the leaven of the Christian people.
«It is shallow and petulant to rail against the political aspects of Constantinianism while ignoring the efforts of Christians of ancient times to stamp the face of Christ on the mores of society, in the ordering of time, in architecture, and law (e.g. prohibition of the exposure of infants, an ancient form of birth control).»
Christ has conquered the whole world, and so it is no wonder that Christians will propose the boldest changes to society at the broadest levels. Our goal, however, is not to run the world, to fix all the world's problems, to impose (like others) a final utopia. It is to accompany the world and to foster true freedom by having the courage to show another way of living.