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.
Larry HurtadoI 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."
Larry Hurtado"Religions" of the Roman world varied. Most of it was ritual practices. There were periodic occasions when cities honored their guardian deities with sacrifices and ceremonies, to ensure that they stayed happy and kept the city safe.
Larry HurtadoSome modern scholars contend that in terms of what "religion" was in that [Roman-era setting], you can't even call Christianity a religion.
Larry HurtadoStudies of the people named and described in earliest Christian texts show that, right from the earliest years, they included craftsmen, merchants, and owners of businesses. Of course, there were also slaves and poor among believers. By at least the second century, there were also believers from upper levels of Roman society.
Larry Hurtado