The capture of Constantinople by the leaders of the Fourth Crusade in April 1204 marks a major break not only in the history of the Byzantine Empire, but also of the East Mediterranean and, one could argue, of the West as well. For the victors, possession of the Byzantine capital promised the possible conquest and occupation of previously imperial territory. For the losers, their Byzantine world was turned upside down by the loss of its nodal point, the metropolitan centre, the ‘queen’ city that had ruled the empire for centuries. On both sides the unexpected results produced new configurations of power: western crusaders, initially recruited for an attack on Muslim Egypt, had to consider how to rule over a Latin empire, while many of the Greek inhabitants of Constantinople were forced to flee in humiliating circumstances. For several turbulent years, these new rulers and new refugees found themselves in unfamiliar conditions, which must have changed their perception of their own identities. Some notion of the fundamentally imperial character of Byzantium appears to have lived on in the claims made by authorities in Constantinople and its rivals, the capitals of Nicaea, Arta and Trebizond, where each tried to sustain the essence of imperial power. In their different ways they reflected a tectonic shift that is manifested in new pluralistic identities.