Before revision: Constantine the Great started his conversion to Christianity because while on campaign he had a dream which prophecised that he would win a battle if he adopted the Chi-Rho as his battle standard.
After revision: Constantine the Great started his conversion to Christianity because while on campaign he had a dream which prophesied that he would win the battle of the Milvian BridgeAccording to ancient authors, if he adopted the Chi-Rho as his battle standard.