This book is not really a history book, but rather a result of discussions conducted by a specialist in the study period: the Rome of Constantine and everything that revolves around it. Let the author tribute: it is very well written and his digressions assimilate easily. Paul Veyne well enough this historic radius for having had the opportunity to be a personal opinion and argued on the thorny problem of the spread of Christianity in the Roman Empire in the fourth century. Obviously other historians do not agree with him, but this is the charm of the "science" historic. The fact remains that a lot of his analyzes seem sensible and bear the stamp of common sense. You can indulge yourself as the author's style is worthwhile.