Some curious questions came in the post to St Augustine in the last years of the fourth century from a Catholic senator in the southern part of what we call Tunisia. I only came across them because I was looking for something else. They entertained me, but answering them must have been a tricky chore for the bishop, since the problems posed sound on the scrupulous side, and scrupulous people find a way of picking holes in the soundest advice.

“Is it permissible,” asked Senator Publicola, “for a Christian knowingly to eat wheat from a threshing floor from which an offering has been made to a demon?” What about a Christian who builds a wall round his property; is he “guilty of murder if people use it to fight and kill enemies from”? So he goes on, under 18 main headings, about hiring a litter in which a pagan has been doing something sacrilegious, or staving off death by starvation by eating meat set before an idol in a deserted temple.