I think that Rodney Stark studies of new religious movements in the modern world give us some insights into the kinds of questions that we can ask about early Christianity.

Galen's observations reflect one of the distinctive features of early Christianity. Roman-era religion was mainly about ritual actions vis-à-vis the gods, and there was little to do with ordering behavior otherwise.

In its Roman-era setting, for example, Christianity was so different that critics of the time referred to it as a "superstition" (meaning a bogus or dangerous religion).

I think Rodney Stark makes a substantial contribution to the study of early Christianity in posing the kinds of questions that he pursues (which reflect his social-science background).

Justin's testimony about becoming a Christian is that he had been searching various philosophical traditions of the time, and then accidentally encountered a man who posed questions that pointed Justin [Martyr ] in a new direction.

Justin Martyr says that he was impressed in his study of the Old Testament, at the seriousness and contents of these writings, and became convinced that Jesus fulfilled these texts.

I offer early Christianity as a case-study to show that the phenomena that we group under "religion(s)" comprise a somewhat artificial category, and that "religions" are not "all the same."