It is an empire without a consciousness of itself as such, constantly shocked that its good intentions arouse resentment abroad. But that does not make it any the less of an empire, with a conviction that it alone, in Herman Melville's words, bears ‘the ark of liberties of the world.

If all history according to Marx has been the history of class struggle, then all international history, it could just as well be argued, has been the struggle between different kinds of Empire vying for hegemony in a world where the only measure was success and the only means of achieving this was through war. Indeed, so obvious is this fact to historians – but so fixated has the profession of International Relations been with the Westphalian settlement – that it too readily forgets that imperial conquest, rather than mere state survival, has been the principle dynamic shaping the contours of the world system from the sixteenth century onwards. Empires, however, were not just mere agents existing in static structures. They were living entities that thought, planned, and then tried to draw the appropriate lessons from the study of what had happened to others in the past.