In the early church, Christians were sometimes accused by unbelievers of bizarre misconducts and offences. They were accused, for example, of being cannibals (they ate flesh and drank blood – a reference to the Lord’s Supper), of committing incest (they referred to each other as ‘brother’ and ‘sister’), and for being ‘atheists’ (they did not believe in the classical Greek and Roman gods), among others, all being misunderstandings and travesties of what they actually believed and practised. Regarding the accusation of being ‘atheists’, Justin Martyr (c. AD 100–165) replied in his First Apology, v:
“Thus we are called atheists. And we admit that in respect of such supposed gods as those (i.e. the gods of ancient Greece and Rome) we are atheists: but not in regard to the most true God, the Father of righteousness and moderation and the other virtues, the God who is without a trace of evil. Him we worship and adore, and his Son, who came from him and taught us of these things, and the host of the other good angels who attend on God and are of god-like nature, and the Spirit of prophecy. These we worship with reason and truth.”
* While the last sentence in the quote seems to grammatically indicate (i.e. by antecedent) that Justin Martyr is saying that Christians also worship angels (to my knowledge, I am unsure whether we can affirm that he actually believed this), I would suggest taking it as a reference to the Father, the Son, and the Holy Spirit.