The second century was a rather curious period in church history. It was a time when Christians were struggling to define themselves, not only in terms of departure from their Jewish roots, but also against the Graeco-Roman world around them. Christianity was still very much a minority movement during this period, forced underground by repeated persecution, and martyrdom was still a frequent reality. Doctrinally a certain amount of fluidity existed, although by the end of the second century concepts of what was acceptable in the mainstream church began to harden and what may have been considered merely ‘extreme’ in the mid-second century became ‘heresy’ by its end.