Nicene and Post-Nicene Fathers, Ser. II, Vol I:
The Life of Constantine with Orations of Constantine and Eusebius.: Chapter LXVII

Chapter LXVII.—That Religion began in the East.

“For since the power of Divine light, and the law of sacred worship, which, proceeding in the first instance, through the favor of God, from the bosom, as it were, of the East, have illumined the world, by their sacred radiance, I naturally believed that you would be the first to promote the salvation of other nations, and resolved with all energy of thought and diligence of enquiry to seek your aid. As soon, therefore, as I had secured my decisive victory and unquestionable triumph over my enemies, my first enquiry was concerning that object which I felt to be of paramount interest and importance.