Nearing the conclusion of his long, several chapter discussion on paganism, Chesterton writes this potent (and I think beautiful) passage on the fall of paganism in the west and the rise of Christianity:
The Old Man of the Forest was too old; he was already dying. It is said truly in a sense that Pan died because Christ was born. It is almost as true in another sense that men knew that Christ was born because Pan was already dead. A void was made by the vanishing of the whole mythology of mankind, which would have asphyxiated like a vacuum if it had not been filled with theology. But the point for the moment is that the mythology could not have lasted like a theology in any case.
Theology is thought, whether we agree with it or not. Mythology was never thought, and nobody could really agree with it or disagree with it. It was a mere mood of glamour and when the mood went it could not be recovered. Men not only ceased to believe in the gods, but they realised that they had NEVER believed in them. They had sung their praises; they had danced round their altars. They had played the flute; they had played the fool
-G.K. Chesteton, The Everlasting Man, p.182