Far too long, historians have accepted the claim that the conversion of the Emperor Constantine (ca. 285-337) caused the triumph of Christianity. To the contrary, he destroyed its most attractive and dynamic aspects, turning a high-intensity, grassroots movement into an arrogant institution controlled by an elite who often managed to be both brutal and lax.
"For the Glory of God: How Monotheism Led to Reformations, Science, Witch-Hunts, and the End of Slavery". Book by Rodney Stark, August 29, 2004.