General and comparative studies of empire – like those of revolution – often suffer from insufficient attention to chronology. Time expresses itself both in the form that empires occur, often in succession to each other – the Roman, the Holy Roman, the Spanish, etc. – and, equally, in an awareness that this succession links empires in a genealogical sense, as part of a family of empires. This article explores the implications of taking time seriously, so that empires are not considered (...) simply as like ‘cases’ of a general phenomenon of empire but are treated as both ‘the same and different’. Concentrating on the European empires since the time of Rome, the article shows the extent to which empires were conscious of each other, seeking both to imitate admired features as well as to escape from those thought less desirable. It also shows the difference between ancient and modern empires, considered not so much as different types as in the differences caused by their location in different points in historical time. Comparative studies of empire, the article concludes, must pay attention to both continuity and change, both similarity and difference. (shrink)