and link to a post I made here about the medieval Church actually encouraging culture even when it wasn't religious.

To make that long wordy post relevant here, I think Tolkien is actually in line with longstanding Christian tradition in his ability to perceive the natural greatness of cultures before they were converted, and in the case of the Anglo-Saxons, or the Germanic tribes generally, it was their appreciation for the heroic virtues which made them receptive to aspects of Christian teaching.

(Btw, Christopher Dawson, besides being a historian, was also a contemporary, fellow countryman, and fellow churchman with Tolkien, so I wouldn't be surprised if they knew each other!)