The Life of Constantine with Orations of Constantine and Eusebius 73A Farther Mention of his Prayers in the Tabernacle.

Now these, and a thousand such acts as these, were familiarly and habitually done by the emperor. And on the present occasion he retired, as his custom was before battle, to the privacy of his tabernacle, and there employed his time in prayer to God. Meanwhile he strictly abstained from anything like ease, or luxurious living, and disciplined himself by fasting and bodily mortification, imploring the favor of God by supplication and prayer, that he might obtain his concurrence and aid, and be ready to execute whatever he might be pleased to suggest to his thoughts. In short, he exercised a vigilant care over all alike, and interceded with God as much for the safety of his enemies as for that of his own subjects.