User blog comment:Jazon Naparleon/Questions of Romans and Mongols/@comment-4727448-20120815054104/@comment-1777104-20120817031424

Red, you make a good point about corelation vs causation. Corelation is a secular way of referring to "providence." The Roman Empire -- the Pax Romana -- was there at the right time for the spread of Christianity. As the Roman Empire began to fall, it gave the Church (the corporate structure of Christianity) the opening to preserve civilization through its organization. The so-called spread of Christianity after that was by means not used in its days of persecution.

And so, if Christianity had not arisen, Rome would have fallen anyway. Case closed. :-)