Saint Augustine

Tractatus in Joh. Evang. VII:

Some counterfeit therefore the spirit which I speak has set up, asthough he would fain redeem by blood his own image, since he knew that by precious blood the human race was redeemed. For evil spirits invent for themselves certain counterfeit representations of high degree, that by this means they may deceive the followers of Christ. To such an extent, my brethren, that these very foes of ours, who delude by their posturing and incantations and devices, mingle with their incantations the name of Christ. And because with poison alone they are unable to lead the Christians astray, they add a little honey, to conceal the bitter taste by the sweet, that the fatal draught may be taken; to such an extent that as I understand at one time the priest of that mitred god [Mithras] was accustomed tosay, "the mitred god himself also was a Christian."

Quaestiones Veteris et Novi Testamenti:

What travesty is it then that they enact in the cave with veiled faces? for they cover their eyes lest their deeds of shame should revolt them. Some like birds flap their wings imitating the raven's cry; others roar like lions; others bind their hands with the entrails of fowls and fling themselves down over pits full of water, and then another whom they call the Liberator approaches with a sword and severs the above-mentioned bonds. Other rites there are which are yet more dishonourable. What shameful mockeries for men who call themselves wise. But because these things are concealed in the darkness they think that they can remain unkown. yet all these, the secret devise and contrivance of foul and maligmant demons, have been dragged to the light and unveiled by the holy Christian faith. For when the faith is preached the hearers of the excellent and sacred truth thus proclaimed have been converted, and ahve abandoned those dishonourable and secret rites, confessing that in their ignorance they have been misled.