This book does not offer a linear history of Christianity during the first centuries ce but attempts to show how Christians met the expectations and challenges of their environments. I am perhaps exceedingly cautious in my analysis of the social history of Christians because the rather qualitative evidence of the sources on the individual actors does not seem to me to provide a sufficient basis for quantitative analyses. In addition, I do not give an explanation for the success of Christianity but offer many reasons why Christians were successful in certain contexts.