Empires: how do they begin? How do they rule? How do they end? What are their complex legacies? These have been perennial questions for historians and political leaders at least since Edward Gibbon’s majestic six-volume rumination on the decline and fall of the Roman Empire. They are conundrums that historians have returned to with renewed vigour over the last decade. Frederick Cooper and Jane Burbank put empire at the centre of a new understanding of global history in 2011 with their landmark Empires in World History. For them, the contemporary world of nation states is a recent creation, principally of the era after 1945. Before that, empires were the norm. Of course, all empires were not the same, but whether it was Rome, China or the Islamic caliphates, all faced the same problem, namely how to develop a strategy of domination among highly divergent populations. Cooper and Burbank concluded that each, in their different ways, arrived at methods that combined repression with manipulation and accommodation.

A parallel development has been the recent attempts to rehabilitate empires. In Britain, the charge has been led