Seas may unite, but they can also divide. In his study of the medieval Mediterranean, John Pryor discerns two simultaneous and quite contrary forces at work. The sea acts not only as a centripetal force bonding together the various peoples around the Mediterranean but also as a centrifugal element separating them and lying at the heart of their distinct historical developments.2 A desire to obliterate the divisions since the late 1940s and to find historical traces of European unity or integration has perhaps led historians and others to underplay the way in which seas may have separated, or been made to separate, the
nations whose maritime frontiers they may mark. It is nonetheless entirely understandable that, in the aftermath of the Cold War and at a time of strong moves towards European integration, there should be considerable interest in the unifying and uniting aspects of the maritime girdle which surrounds so much of the continent.