Epistle of Marcus Aurelius to the senate, in which he testifies that the Christians were the cause of his victory.
Having then examined my own position, and my host, with respect to the vast mass of barbarians and of the enemy, I quickly betook myself to prayer to the gods of my country. But being disregarded by them, I summoned those who among us go by the name of Christians. And having made inquiry, I discovered a great number and vast host of them, and raged against them, which was by no means becoming; for afterwards I learned their power. Wherefore they began the battle, not by preparing weapons, nor arms, nor bugles; for such preparation is hateful to them, on account of the God they bear about in their conscience.
Therefore it is probable that those whom we suppose to be atheists, have God as their ruling power entrenched in their conscience. For having cast themselves on the ground, they prayed not only for me, but also for the whole army as it stood, that they might be delivered from the present thirst and famine. For during five days we had got no water, because there was none; for we were in the heart of Germany, and in the enemy’s territory. And simultaneously with their casting themselves on the ground, and praying to God (a God of whom I am ignorant), water poured from heaven, upon us most refreshingly cool, but upon the enemies of Rome a withering1920 hail. And immediately we recognized the presence of God following on the prayer-a God unconquerable and indestructible.
Founding upon this, then, let us pardon such as are Christians, lest they pray for and obtain such a weapon against ourselves. And I counsel that no such person be accused on the ground of his being a Christian. But if any one be found laying to the charge of a Christian that he is a Christian, I desire that it be made manifest that he who is accused as a Christian, and acknowledges that he is one, is accused of nothing else than only this, that he is a Christian; but that he who arraigns him be burned alive. And I further desire, that he who is entrusted with the government of the province shall not compel the Christian, who confesses and certifies such a matter, to retract; neither shall he commit him. And I desire that these things be confirmed by a decree of the Senate. And I command this my edict to be published in the Forum of Trajan, in order that it may be read. The prefect Vitrasius Pollio will see that it be transmitted to all the provinces round about, and that no one who wishes to make use of or to possess it be hindered from obtaining a copy from the document I now publish.
Roberts, A & Donaldson, J. The Researchers Library of Ancient Texts; Volume 2. Pg 162. Thomas Horn. Defense 2011