One of the very first secular references to Christians and Christians practices at length is Pliney's letter 96 to Trajan (written between 111 and 113 CE). He is asking Trajan for instruction regarding religious persecution with regard to Christians. While he does not think highly of the religion one paragraph stands out quite strongly, where he describes how he interrogates the leaders of a small house church:
They asserted, however, that the sum and substance of their fault or error had been that they were accustomed to meet on a fixed day before dawn and sing responsively a hymn to Christ as to a god, and to bind themselves by oath, not to some crime, but not to commit fraud, theft, or adultery, not falsify their trust, nor to refuse to return a trust when called upon to do so. When this was over, it was their custom to depart and to assemble again to partake of food--but ordinary and innocent food. Even this, they affirmed, they had ceased to do after my edict by which, in accordance with your instructions, I had forbidden political associations. Accordingly, I judged it all the more necessary to find out what the truth was by torturing two female slaves who were called deaconesses. But I discovered nothing else but depraved, excessive superstition.