* The original oral version of this essay was delivered on 6 February 2003 in the Great Hall of King’s College London, as the Thirteenth (Sir Steven) Runciman Lecture. For the invitation to deliver the lecture and for the accompanying resplendent hospitality I am deeply grateful to Matti and Nicholas Egon, the very models of enlightened benefaction. For other services related to the Lecture, I must also thank most warmly my friends and colleagues, Professor Judith Herrin, lately Director of the Centre for Hellenic Studies at King’s, her successor, Dr Karim Arafat, and his and my former graduate supervisor at Oxford, Professor Sir John Boardman (who did me the honour of introducing my Runciman Lecture).

Several audiences on both sides of the Atlantic, and of the St George’s and English Channels, have heard various versions of this paper, and one or two others have very kindly read and commented on various written versions. To all of these, too numerous to enumerate exhaustively here (but I must mention Johannes Haubold and David Pritchard), I offer my heartfelt thanks.