The theme of this book is friendship, an area of ethics which is not of central concern nowadays, especially when regarded as a relationship of affection between members of the same sex. And although it may in some form still have a part in our everyday lives, possibly offering a pleasant means of passing our spare time, we do not tend to regard it as something to which definite rules of conduct apply. Family relations have taken centre stage in our society and friendship has consequently moved into the wings. The modern view of friendship has little in common with that held in antiquity, even if occasionally, in literary writings, we may find sentiments expressed about friendship which seem to conform to generally accepted ideas on the subject, handed on through the ages and discovered anew to be accurate by each generation of articulate people, as when Charlotte Brontë writes in a letter of I March 1847, ‘To keep friendship in proper order, the balance of good offices must be preserved, otherwise a disquieting and anxious feeling creeps in, and destroys mutual comfort.’ But in general it is not a topic about which we theorise or which is regarded as demanding or problematic.

It may then seem surprising that it should have been such a popular topic and so highly valued in Greece and Rome and even more surprising that it should have been regarded as important within Christianity.