This is from the 15th chapter of Gibbon’s Decline and Fall of the Roman Empire:
Our curiosity is naturally prompted to inquire by what means the Christian faith obtained so remarkable a victory over the established religions of the earth. . . . It will, perhaps, appear, that it was most effectually favored and assisted by the five following causes:
I. The inflexible, and if we may use the expression, the intolerant zeal of the Christians . . .
II. The doctrine of a future life, improved by every additional circumstance which could give weight and efficacy to that important truth.
III. The miraculous powers ascribed to the primitive church.
IV. The pure and austere morals of the Christians.
V. The union and discipline of the Christian republic, which gradually formed an independent and increasing state in the heart of the Roman empire.
Only saying.