The Problem(s) of Empire

I EMPIRE, KNOWLEDGE AND EPISTEMIC AUTHORITY

Oxford University Press is the largest university press in the world. It has been in continuous operation since 1586, making it the second oldest university press after Cambridge University Press (1534). From its imposing complex in Jericho, the stylish suburb of Oxford, and its many satellite offices around the world, including Delhi, Chennai, Kolkata, Karachi, Hong Kong, Cape Town, Nairobi, Dar es Salaam, Melbourne, Toronto and New York — the overlap with former territories of the British Empire is conspicuous — it produces an unparalleled number of academic publications every year and occupies a dominant position in the authentication of knowledge and its dissemination across the globe. In 2022–23, for example, the press published no fewer than 1,777 new academic titles, available in 193 countries and translated into 45 languages (including Somali and Quechua, as the press's 2022–23 Annual Report breathlessly announces). And revenues are substantial: £825,000,000 in sales last year alone.¹ A bastion of prestige, global in reach but with a clear centre, and sitting comfortably within the inner citadel of a hierarchical, worldwide ecosystem of knowledge-making, Oxford University Press can be seen as a quasi-imperial operation in its own right.²

It seems fitting, then, that OUP should be the juggernaut to bring out this new world history of empire. In two substantial volumes, totalling 61 chapters and just under 2,000 pages, written by a team of 62 experts and ably edited by Peter Bang, C. A. Bayly (who died in 2015) and Walter Scheidel, The Oxford World History of Empire (OWHE) delivers a comprehensive and confidently authoritative account of the phenomenon that we label, as a matter of convenience, ‘empire’, from the third millennium b.c.e. right up to the present day. Some readers may perceive a vaguely ‘imperial’ feel to the publication itself. As an accessible reference work that merges conceptual synthesis with selective narrative, OWHE necessarily schematises, summarises and simplifies an impossibly messy historical reality that stretches over several millennia. Viewed in this light, these hefty and expensive volumes can be read as an ambitious project, as much a commercial as an intellectual one, to make legible to readers a long-term global history and contemporary world order — or, rather, one version of that history and order — in which empires, old and new, have predominated. OWHE is itself part of the legacy of empire, in other words, and as a commanding and totalising compilation of knowledge about empire that mirrors imperial attitudes, is arguably parasitic upon it.

At stake in framing the work in this way is the question of epistemic authority. Not everyone gets to tell the story of empire from their own perspective or positionality, nor does every version of imperial history get the imprimatur of Oxford University Press, with all of the ‘soft power’ that this global brand embodies. In this regard, it must be said that OWHE reads like the product of an age that has already passed.³ It is not that there is much explicit cheerleading for empire here.⁴ It is rather that the mostly top-down perspective and coolly social-scientific idiom of much of the text strikes a somewhat discordant note at a time when all systems of power are under sustained and aggressive interrogation.

This does not mean that OWHE should be ignored or discarded. Far from it. This is a serious and important work of scholarship, and for those willing to plumb its depths there are many empirical and conceptual riches on offer. To begin to explore them, I will first provide a summary review of the two volumes and deliver a preliminary assessment of strengths and weaknesses (Section II). I will then turn to the perennial problem of the ontology of empire, thinking through the various typologies and definitions of ‘empire’ proposed by the editors and authors and attempting to situate empires in relation to other durable and spatially extensive configurations of power (Section III). From this abstract overview of empires in general, I will then turn to the specific case of the Roman Empire in particular, placing it in comparative perspective in three ways: first, by considering its long and influential afterlife; second, through a set of quantifiable criteria; and third, by probing what is typical and what is distinctive about the Roman Empire when viewed through the comparative lens afforded by OWHE itself (Section IV). A brief, concluding discussion considers whether or not we are now living in a post-imperial world, and how a better understanding of the history of empires, including the Roman Empire, can help us to chart a more equitable and sustainable future (Section V).

II A PRELIMINARY ASSESSMENT

OWHE is divided into two volumes of unequal length. The division reflects two fundamentally different approaches to the problem of empire, one nomothetic and the other idiographic. The first, shorter volume (551 pages), ‘The Imperial Experience’, comprises a series of conceptual and thematic essays on empires as such. Here we find definitions, metrics, patterns and general characteristics. In the second volume, ‘The History of Empires’ — a behemoth at over 1300 pages — 44 case studies provide concise overviews of different historical instantiations of ‘empire’, beginning with pharaonic Egypt and concluding with the United States in the twenty-first century. These chapters cover the expected topics: origins, growth, material resources, administration, culture and ideology, resistance, decline and fall, and so on. The two volumes are perhaps best seen as an interpretive essay and a reference work respectively. Given their disparate subject matter and scope, it is a good guess that some readers will read the first volume more or less in its entirety, but most will only consult the second as relevant to their teaching or research interests. Before assessing the project as a whole, then, let us consider each volume in turn.⁵

The first volume opens with a long chapter (nearly 90 pages) by Bang (‘Empire — A World History: Anatomy and Concept, Theory and Synthesis’), an ambitious attempt to establish a conceptual and intellectual foundation for the work as a whole. An admirably clear treatment of empire, both analytically and empirically, this chapter will probably displace Stephen Howe's volume in Oxford's Very Short Introduction series as the first port of call for anglophone newcomers to the subject.⁶ Vol. 1 then follows with fifteen chapters organised into four discrete sections: ‘Systems of Power: Military, Economy, Elites’ (chs 2–5); ‘Cultures of Power: Symbolic Display, Knowledge, Belief, Discourse’ (chs 6–10); ‘Disparities of Power: Hierarchies, Resistance, Resources’ (chs 11–14); and ‘Memory and Decline’ (chs 15–16). Three principal themes can be discerned: configurations of imperial space; different modes of cultural and ideological integration; and competition, both inter- and intra-imperial, and often violent, over territory, material resources and authority.

An empire — whatever else it is — is not simply an illusion that resides in the collective imagination (though it is that, too), but rather a structure and set of processes with very real effects ‘on the ground’. In order to comprehend the nature and impact of empire, therefore, it is essential to examine its peculiar spatial dynamics. The first volume offers several useful perspectives on the problem. In a characteristically lucid presentation of some relevant data (ch. 2), Scheidel shows that, in terms of surface area, empires have grown ever larger over the long term, with dramatic escalations in the sixth century b.c.e. and seventeenth century c.e. and peaking, globally, on the eve of World War II (1.91–100).⁷ These imperial systems have tended to cluster in temperate Eurasia and the adjacent steppe zone (1.108–10), with the largest subject populations in East Asia (1.104).

Even in spatial terms, though, surface area is not by itself the key criterion. What really matters is how the scale of empire — its practical distances, as experienced in real time, and as inflected by variable geography, technology and transportation infrastructure — structured relationships between widely scattered sites and far-flung regions, with intra-imperial movements and interactions that were necessarily slow-moving, multiply mediated and constantly subject to negotiation and various acts of translation, all of which gave rise to the underlying diversity (ethnic, cultural, ecological, and so on) that is a characteristic of empire.⁸ Core-periphery models, mostly inherited from world-systems theory, provide one well-known heuristic device to describe the long-distance relationships characteristic of empire.⁹ Thus we are reminded in John Haldon's chapter on political economy (ch. 5) that the ‘dialectic’ between core and periphery not only channels the flow of resources within empires (1.193–4) but also, more generally, gives shape and energy to imperial networks of power and authority (1.180). To go beyond the schematism intrinsic to the core-periphery model, however, it is necessary to probe in more empirical detail how it was that different nodes, links, corridors and clusters of social power were actually stitched together in the service of empire.¹⁰ Several contributions reveal what is at stake in this question. Alf Hornborg's chapter on ecology (ch. 13) charts the long-distance — and dramatically unequal — movements of goods, especially in the context of the European colonial empires (1.473–9), while regional and global flows of human labour, addressed in James Beattie and Eugene Anderson's chapter on empires and environments (ch. 14), reveals how the interdependence of ecological resources, including labour, underpins many imperial projects. And it is through emergent constellations of long-distance, networked power in the modern period, according to Christopher Chase-Dunn and Dmytro Khutky (ch. 3), that we may be headed towards the rise of a ‘true world state’ (1.137). All three chapters shed light on how the various asymmetries characteristic of empire are created, replicated and intensified by the sheer scale of imperial operations.

Scale matters in other ways, too. It was no simple matter to hold such large political systems together. Effective integration was a constant challenge. Imperial integrity (such as it was) was achieved partly through law, as Caroline Humfress illustrates in an elegant discussion (ch. 7), and partly through what Jane Burbank and Frederick Cooper call ‘the politics of difference’ (ch. 11), reprising the thesis of their 2010 book on the strategic inclusion and exclusion of different groups and populations. But imperial integration could also arise from the collective consciousness of imperial subjects. This is a second key theme to emerge from the first volume. Some forms of (elite) cultural integration could be generated by imperial literatures, as Javed Majeed shows (ch. 10), such as the epic poetry of ancient empires or the novels of their modern successors (1.343–5), or by imperial monuments and ceremonial, as we are reminded by Cecily Hilsdale (ch. 6). But the constraints of literacy and the immobility of most forms of imperial display put hard limits on empire-wide integration through texts or monuments. Deeper and more widespread effects were realised through religious practices and beliefs (ch. 9, Amira Bennison), which produced the fiction of a ‘divinely ordained social order’ (1.322), and through knowledge, especially the normative ordering of time and space, which provided a cognitive map for making sense of the world (ch. 8, Laura Hostetler, drawing heavily on Scott 1998). An especially valuable insight from the first volume is that the imperial imaginaries to which texts, monuments, religion and knowledge gave rise could have real-world, material consequences. Haldon is excellent on this point, devoting a section of his chapter on political economy to ‘ideological resources’ and their crucial legitimating function (1.202–6), while Hornborg frames his mostly materialist treatment of imperial ecologies with reference to the ‘cultural ideologies’ within which control over ecological resources was ‘embedded’ (1.438). In general, the first volume is strong on culture (broadly defined) both as a discursive domain in its own right and as a key component of imperial rule.

Another consistent theme in these chapters is that of competition (even if not explicitly identified as such). Empires rose and fell through collective, zero-sum competition over territory and resources, and, as large-scale configurations of power, served as frameworks within which high-stakes competition for wealth, authority and honour, both collective and individual, was endemic. The ultimate arbiter of success in the sphere of imperial competition was violence. Indeed, organised violence was essential to the making and reproduction of empires.¹¹ Ian Morris's chapter on military organisation (ch. 4), a standout contribution, sets out the basics. He emphasises the challenges of financing armed forces (observing a sequential shift over time from plunder to tax-and-spend to debt financing: 1.162–5), the structural competition between central and peripheral agents, and the long-term evolution of military technologies, from stone weapons and crude fortifications to mass infantries and navies and from guns and ocean-going ships to thermonuclear weapons and computerised warfare (neatly summarised in table 4.1, ‘More Than 2 Million Years of Revolutions in Military Affairs’, 1.170). Centrally coordinated violence was necessary, not only for initial conquest but also to engage in the turbulent world of inter-imperial competition, which Chase-Dunn and Khutky illustrate well in their stimulating chapter on imperial geopolitics (ch. 3).

That empires often fell apart as a result of large-scale violence is confirmed in many of the case studies in vol. 2, even if this is not the focus of Kim Wagner's chapter on resistance and rebellion (ch. 12); indeed, one of Wagner's important points is that much resistance is non-violent (1.426–7). Some resistance was played out in the contest over ideas, norms and values, and this too can be seen as a form of intra-imperial competition. In the religious sphere, for example, sectarianism, mysticism and millenarism have each functioned as what Bennison calls an ‘idiom of subversion’ (1.337–8), while imaginative literatures, as Majeed remarks, drawing on the literary personae of Chinua Achebe and Salman Rushdie, can ‘enact multilingual and cross-cultural sensibilities … as part of a repertoire of techniques to reframe and subvert imperial legacies and their ideological binaries’ (1.360). More generally, the separation of imperial subjects into ‘winners’ and ‘losers’, a leitmotif of the volume (most fully articulated by Burbank and Cooper, ch. 11), is yet another form of competition — not openly violent (usually), but nevertheless structured, ultimately, by the logic of coercion. After all, empires were socio-political orders defined by inequality, asymmetry and hierarchy, and the violence that brought such orders into being was never too far from the surface.¹²

Overall, the first volume of OWHE is an effective study of empires as systems of power. It is an unapologetically top-down account, with a consistent focus throughout on institutions, statecraft, political economy and elite cultural production.¹³ What is mainly missing here, despite the subtitle of the volume, is precisely ‘experience’ — and in particular for those who were usually far removed from the levers of power and authority: women, children, rural peasants, marginalised groups and (above all) enslaved persons. There is very little here about their particular subjectivities. Of course, it may be the case that there has been no discernible imperial ‘experience’ as such, for these or any other groups, nothing that could be generalised across cases or that is specific to empires as a particular social and political form. That the question of what it has really been like to experience life as an imperial subject is hardly even broached, though, is a little disappointing.

It must also be said that not all the chapters are up to the stated task of the first volume. A number begin from first principles, offer explicit definitions, articulate key concepts and seek to provide general accounts of a problem that can then be applied to specific historical cases. But others retreat rather quickly either into more circumscribed bodies of evidence, such as Hilsdale's contribution, which purports to cover imperial monumentalism, ceremony and pageantry (ch. 6) but is in fact a sequence of case studies on obelisks in pharaonic Egypt, Augustan Rome and Byzantine and Ottoman Constantinople, or onto the safe ground of the specific periods and places in which the authors specialise, such as the chapter by Bennison (ch. 9), nominally on religion and empire in general but mainly on Islamic empires in particular, or by Wagner (ch. 12), which addresses the universal problem of resistance and rebellion, but almost entirely through a case study of resistance to the European colonial empires in the nineteenth century. There is plenty of valuable scholarship on offer in every chapter, and the bibliographies will make an excellent resource, but the generalising ambition of the first volume — designed, as Bang promises in the prolegomena, ‘to reveal broader patterns for a wide range of thematics’ (1.xxv) — is not fully realised.¹⁴

Vol. 2 of OWHE, by contrast, is rather more successful on its own, rather different terms — ‘to assemble a world history from a set of individual imperial histories’, as Bang puts it, with a focus on chronology, military foundations, political economy and society and culture (1.xxvi). In general, the case studies in vol. 2 deliver the goods. They are clear, concise, informative and reliable. The 45 chapters are divided into eight parts: ‘I. Bronze to Iron Age’ (chs. 1–5), from third-millennium b.c.e. Egypt to Republican Rome; ‘II. The Classical Age’ (chs. 6–11) and ‘III. The Ecumenic Turn’ (chs. 12–17), covering the rise and fall of Eurasian empires up through the fifteenth century; ‘IV. The Mongol Moment’ (chs. 18–23), with a narrative mostly centred on the Asian steppe (chs. 18–23); ‘V. Another World’ (chs. 24–5), on the precolonial Americas; ‘VI. The Great Confluence’ (chs. 26–32), on ‘agrarian consolidation’ (Ottoman, Mughal and Qing Empires) and the rise of the European colonial empires (Spanish, Portuguese, Dutch, British) through the mid-eighteenth century; ‘VII. The Global Turn’ (chs. 33–40), focusing on the European empires up through World War I; and ‘VIII. The Twentieth Century’ (chs. 41–4), covering Germany and Japan, decolonisation, the Soviet Union and America's ‘global imperium’.¹⁵ Frederick Cooper's epilogue contemplates the future, still rather opaque, of a post-imperial global politics (ch. 45). The groupings and periodisations are sensible, and the sequence of introductory essays that frame each of the eight parts, all composed by Bang, situate the different empires in their wider historical contexts and serve as a very useful orientation for this world history.

In terms of thematic emphases, the case studies in the second volume largely correspond to those of the first. Matters of space, territory and transregional exchange recur throughout. The asymmetric relationship between core and periphery emerged right from the beginning, in the Ur III state in Mesopotamia in the late third millennium b.c.e. (ch. 2, Piotr Steinkeller), but even the early empires were not always territorially contiguous in the ways that our monochromatic maps imply. The dominance of the Assyrian empire at its height (eighth-seventh centuries b.c.e.), for example, ‘never became continuous or fully integrated’ (2.89), while in the Americas, the map of the sixteenth-century Aztec Empire (ch. 24, Michael Smith and Maëlle Sergheraert) ‘shows many blank areas’ (2.678). Examples could be multiplied. One takeaway is that when empires became truly global in reach — first and most spectacularly with the British Empire in the nineteenth century (ch. 33, Bayly) — the difference from earlier imperial systems was one not of kind but of degree. The early empires, too, were also (in effect) widely scattered clusters of social power linked together by a mix of institutions and relationships. This is an important point to which we will return.

But what really mattered in terms of scale was, again, not size as such but rather the nature of the spatial relationships characteristic of empires and the forging within and across them of multiple, overlapping, supra-regional networks. Vol. 2 provides plenty of relevant material even just for the ‘land-based’ empires, from imperial precursors to the Silk Road (under the Kushan Empire in the second century c.e.: ch. 11, Craig Benjamin) and the integrated East Asian maritime zone (under the Tang dynasty, 618–907 c.e.: ch. 13, Mark Lewis) to empires as catalysts for long-distance trade, such as the eighth-century Caliphate (ch. 12, Andrew Marsham), which united the worlds of the Mediterranean basin and Iranian plateau (and their commercial goods: 2.362–3), or the Mughal Empire (ch. 27, Rajeev Kinra), which did the same in the sixteenth and seventeenth centuries for the trans-Indus corridor running from Persia to Bengal (2.774–5), or the Comanche Empire (ch. 38, Pekka Hämäläinen), which underpinned ‘one of the great exchange systems of the Western Hemisphere’ in the mid-nineteenth century, revolving around horses, guns, iron tools, textiles, corn and squash (2.1039). Such commercial networks were hardly altruistic, of course. As Hämäläinen puts it with respect to the Comanches, ‘Their ascendancy rested not on sweeping territorial control but on a capacity to connect vital economic and ecological nodes — trade corridors, grassy river valleys, grain-producing peasant villages, tribute-paying colonial capitals — which allowed them to harness resources without controlling societies’ (2.1048). As a strategy of rule, this ‘harnessing of resources’ was surely most effective when executed on an imperial scale, as these chapters show.¹⁶

The problem of cultural integration and imperial legitimation, a central theme in the first volume, is also prominent in the case studies in vol. 2. Some degree of collective buy-in was imperative for all empires — coercion is always necessary but never sufficient for the long-term stability of states.¹⁷ One secular trend that emerges from these case studies is defined by increasing complexity, as unifying ideologies shifted — broadly, and with plenty of overlap — from the political authority of kings to the cosmic authority of divine legitimation to the more elaborate bundles of norms, values, rights and freedoms that modern imperial regimes have promised to their subjects.

Kingship was the vital institution for the early empires, not only as a uniquely effective coordinating agency but also as a uniquely resonant unifying symbol. Vol. 2 offers striking illustrations from pharaonic Egypt (ch. 1, Juan Carlos Morena García, esp. 2.38–9), Mesopotamia (2.65), Assyria (2.95–6) and the Achaemenid Empire (550–330 b.c.e.: ch. 4, Matthew Waters, esp. 2.126–8), as well as from subsequent imperial formations in late antiquity, such as the Sasanian Empire (224–651 c.e.: ch. 10, Matthew Canepa, esp. 2.314–17), and the middle ages, such as the Byzantine Empire (ch. 16, Anthony Kaldellis, esp. 2.460–1). Religion (broadly defined) was also important for the cohesion of the early empires, but played an even larger role with the rise of the great monotheistic religions.¹⁸ This was true of the Islamic Caliphate (2.370–4), upon which the Ottoman Empire (ch. 26, Dariusz Kolodziejczyk) self-consciously modelled its Muslim patronage in the sixteenth century (2.736); the Spanish Empire (ch. 28, Josep Delgado and Josep Fradera), which promoted an empire-wide ideal of Catholic universalism (in the face of Protestant opposition: 2.794–5); and the Russian Empire (ch. 35, Dominic Lieven), which was forged in part through an effective alliance between its rulers and the Eastern Orthodox Church, but which lost momentum in its attempt to transfer the basis for imperial belonging from religion to a weakly felt Slavic ethnicity (2.974–6). These chapters demonstrate convincingly how spiritual and divine authority helped to undergird the temporal power of imperial states.

In the nineteenth century, we find forms of cultural integration and ideological messaging that appealed to different logics. For the British Empire, this new package of imperial ideals and values can be seen as an expression of what Pocock (1975) called ‘civic republicanism’, a mix of doctrines from across the political spectrum that included bureaucratic paternalism, classical liberalism and a nascent democratising creed (ch. 33). The paternalistic element was more pronounced in the French variant on this cluster of ideas (ch. 34, David Todd), the infamous mission civilisatrice, which combined Orientalist erudition, scientific racism and the ‘emancipatory universalism of French republicanism’ in order to bring civilisation to the ‘inferior races’, as the late-nineteenth-century French Prime Minister Jules Ferry put it (2.941–6). A self-serving mix of justification and persuasion has characterised the imperial(ist) ideologies of the United States, too. These ideas have evolved from a Protestant-infused claim of ‘Manifest Destiny’ in the nineteenth century, which helped to propel territorial expansion across the North American continent (beautifully sketched by Amy Greenberg, ch. 37), to a blizzard of advertised goods in the twentieth and twenty-first (ch. 44, Andrew Preston), from Wilsonian principles of democracy and national self-determination (2.1231–3) and post-war declarations of individual freedom and human rights (2.1234) — the latter in self-conscious opposition to the competing set of ideals promoted by the Soviet Union (ch. 43, Geoffrey Hosking) — to the 1990s ‘Washington consensus’: free markets, privatisation, deregulation and floating exchange rates (2.1242), a set of neoliberal ideals systematically framed and communicated as the universal benefits of an American international order. This is a long way from the cosmic, spiritual and ethical assertions of earlier empires, but the legitimating function is arguably the same. It is one of the virtues of the second volume, which is quite strong on culture and ideology in general, that it prompts such comparative reflections — a reward for those who read from beginning to end.

Several other themes are woven throughout these case studies, any one of which would repay closer attention than is possible here. As we have seen, all empires have been built upon organised violence, in one way or another, and many chapters include informative narratives of the military conquests that propelled some groups to positions of domination over other groups.¹⁹ Those who prefer broadly materialist explanations for the underlying motivations and ultimate causes of empire will find their positions confirmed here, as the struggle for control over resources, and the imperative to manage them at supra-regional scales, is omnipresent.²⁰ Another central theme here is the nature of imperial administration — an acute challenge for most empires, because of the often insuperable challenges of time and space — a topic only indirectly covered in vol. 1 (mainly in Humfress’ chapter on law, ch. 7) but consistently addressed in these case studies; the same goes for taxation and fiscal architecture, effectively sketched by Haldon in the first volume (ch. 5), but much more to the fore in these chapters. We will return to both topics when we consider the Roman Empire in comparative perspective (below, section IV).

The overall impression conveyed across these 44 case studies is one of empires as complex and fluid frameworks, both institutional and personal, for sustained control over large territories and their respective resources and peoples. We can also perceive, quite clearly, the enormous difficulties in building imperial systems and maintaining them over the long term. In this regard, the second volume is entirely consistent with Bang's summary observation in the prolegomena (1.xxvi, taking his cue from Mann 1986) that the central problem for all empires is that of ‘organizational capacity and logistical constraints’. To this I would add the critical importance of cultural production and ideological integration, which many of these chapters suggest was also necessary for the making and (especially) sustaining of empires. Where the volume falls a bit short is in its rather thin social histories of empire. As in volume one, the experience of non-elite men, and especially of women and enslaved persons, barely registers. It is true that some attention is paid to the variable experiences of indigenous populations, especially in the context of the European colonial empires, but the lens is rarely trained on them for very long.²¹ The second volume of OWHE is an invaluable reference work on the rise and fall of empires over the course of several millennia of historical change, with rich empirical treatments of how empires operated as systems of power, but readers mainly interested in what was happening underneath the colourful pageant of kings, armies and governing and financial institutions, and in what life was like ‘on the ground’ for the sub-elite strata that have constituted the bulk of all imperial populations, will have to look elsewhere.

III TYPOLOGIES AND DEFINITIONS

OWHE presents the reader with a very rich tapestry of states, domains, systems, structures and processes that can be seen — in one way or another (and therein lies the interpretive challenge) — as ‘empires’. Making sense of it all is no easy task. One way to come to grips with the highly variegated historical phenomenon of empire is to group smaller subsets of empires into meaningful categories. The distribution of the 44 case studies into eight discrete sections, mostly defined by chronology, is a start. Several of the thematic chapters gesture to a putative distinction between ancient (Eurasian) empires and their modern (mostly European) successors, whether defined in terms of ‘tributary’ versus ‘commercial’ (e.g. 1.128–9, 288) or ‘agrarian’ versus ‘colonial’ (e.g. 1.182–6, 214–16, 2.976) modes, with the year 1492 serving as a convenient dividing line between the former and the latter (1.440).²² Such elementary observations suggest two main ideal types of empire in world history: (i) ancient/agrarian/tributary/land-based and (ii) modern/commercial/fiscal/maritime, each with its characteristic forms of institutional order and social control. This is hardly an original typology, of course.²³ But one of the more intriguing conclusions of OWHE, which runs almost directly counter to the conventional narrative, is that it was in fact the older, Eurasian, agrarian empires that were stronger and more stable than their modern European counterparts, rather than vice versa (1.xx, 11–12, 77–8). This comparative stability is attributed to what Bang calls ‘hegemonic monopoly’, as ‘the process of state-formation generated a forceful current’, in his words, ‘that ran contrary to fragmentation’ (1.77). The case studies assembled here mostly support this claim. The schematic distinction between these two ideal types of empire is not a bad first step, then, and can be useful for Roman historians to think with.

Another way to make sense of empire is to delineate it, as a political form, through contradistinction. The modern nation-state serves as a convenient point of contrast here, and several authors underline structural differences between empires and nations. Burbank and Cooper, while acknowledging some overlap between empires and nations, nevertheless assert the propensity of the one towards ‘heterogeneity’ within a ‘complex polity’, and the other towards ‘homogeneity’ (1.375). In her discussion of the legal apparatus of empire, Humfress posits a similar dichotomy, observing a ‘basic contrast between plurality (associated with empire-states) and monism (the “one state-one society-one law model” associated with nation-states)’ (1.267). If we see empires as states, then we can recognise some points of intersection with nations while also pinpointing other points of departure, which seem to be more salient, in both political and cultural terms.²⁴

OWHE provides some manageable, chronological groupings of empires, a simple taxonomy of ideal types and a helpful distinction between empires and nations. So far, so good. The moment we venture away from the safe ground of abstract theorisation and into the dense thicket of actual historical cases, though, things become a little trickier. Consider, for example, just the following pairs of empires: the Mongol and the Athenian Empire; the Mughal and the Inca Empire; and the Portuguese Empire and Qing Dynasty.²⁵ Each pair is a glaring mismatch, whether in terms of scale, governmentality or historical development, and it is difficult to see how the two polities in each of these pairings might go together, even within the most capacious typological rubrics. And there are several other states, polities and domains that do not seem to fit here at all, such as the Ptolemaic Kingdom, or the Carolingian dynasty, or the late medieval Delhi Sultanate, or the nineteenth-century West African dominion we now call the Sokoto Caliphate.²⁶ The volumes under review offer a sweeping ‘world history’, but whether it is really a world history of ‘empire’ as such is debatable.

And this brings us, unavoidably, to the elusive problem of definitions. It is difficult to imagine a single definition of ‘empire’ that would be analytically rigorous and precise, comprehensive and satisfactory to all scholars.²⁷ Nor does OWHE attempt to dictate one. The editors do not endorse an ‘official line’ on the definitional question, and it is clear that individual authors have had ample freedom to work with their own understandings of the term. The formal definitions on offer run from lapidary declarations — ‘invasion, conquest, and rule’ — to extended meditations on different theoretical and normative positions.²⁸ Most authors operate with a loose bundle of criteria, and usually settle on composite definitions that emphasise scale, heterogeneity (cultural and ethnic), hierarchy, rule, and forceful subordination of multiple territories, increasingly peripheral, to a dominant centre (e.g. 1.156–7, 342, 523–5, 2.533). Whether such criteria stem, self-consciously or not, from preconceived notions about what an empire ‘should’ look like — and whether such notions have themselves arisen from the legacies of the Roman and British Empires in particular — are important questions to which we will return.

Whatever empire is or is not, in any case, it is certainly a ‘fuzzy set’ — and the definitional edifice can look a little wobbly when we consider the edge cases like those noted above. In fact, some authors come close to disavowing the label entirely. Kaldellis, for example, suggests that the Byzantine Empire — or, rather, ‘Romanía’, as he calls it — was ‘less of an “empire” and more a “monarchy of the Roman people”, a system of self-governance’ (2.457). Bruce Hall introduces his chapter on the fifteenth- to sixteenth-century Songhay Empire of West Africa (vol. 2, ch. 23) with the observation that ‘redemptive uses of “empire” in the writing of African history have tended to obscure the nature of large-scale polities in Africa, putting them always in implied comparison with empires elsewhere’ (2.648). And John Miksic, in an intriguing chapter on Śrīvijaya (vol. 2, ch. 14), a ‘very slender polity’ (2.352) which oversaw maritime commerce in and around the Strait of Melaka for several hundred years (c. 680–1025), admits that it perhaps ‘ought to be classified as a consortium or league of ports’ (2.422) — a designation that is consistent with Bang's introduction to the section (2.348–53), in which the whole of Southeast Asia around the turn of the first millennium c.e. is deemed ‘still too young to sustain vast empires’ (2.352). With such cases, we seem to have wandered rather far away from the understanding of ‘empire’ that prevails in most of the rest of OWHE.

The definitional problem that bedevils the comparative study of empires is intrinsic to all macroscopic, comparative analysis of historical phenomena.²⁹ Some historians will be tempted to dismiss the whole endeavour and leave such theorisation and taxonomic thinking to others in order to get on with the practical business of narrative, documentation and description. This temptation should be resisted, though, because something important is lost when our analytical categories are left muddled or unexamined. If we lump too many different states and systems under the category of ‘empire’, we may lose sight of what is typical and what is distinctive about any one empire — and that forecloses a lot of interpretive ground. As Marc Bloch put it in his discussion of abstraction, classification and ‘nomenclature’ in historical analysis:

We merely group facts, as concrete as we could wish, under an expressive name. The similitude of these facts, which the name quite properly seeks to signify, is itself a reality. In themselves, therefore, these terms are entirely legitimate. Their true danger derives from their very convenience. If ill-chosen or too mechanically applied, the symbol (which was there only to assist the analysis) ends by dispensing with analysis.³⁰

One thing that we can say about all the polities included in OWHE, at a minimum, is that they were all spatially extensive, networked configurations of unevenly distributed power. But that is also true of many nation-states and, indeed, of those transnational networks of capital that have proliferated in our globalised era (see below, Section V). What seems to distinguish empire from these other state and non-state forms is the combination of scale, duration, a peculiar form of territoriality, limited infrastructural capacity, pronounced centralisation and (perhaps above all) a high degree of internal differentiation, especially in cultural terms.³¹ Whether all of the polities included here meet all of these criteria for ‘empire’ — or even those criteria articulated in the work itself — is doubtful; the fact that not all of the case-studies even make it onto Scheidel's tabular list of 82 empires (table 2.1, 1.92–4) is revealing. But the more inclusive selection principle of OWHE does have a real benefit in that it provides more empirical fodder for historical comparison. In this sense, bigger is better. And that becomes clear when we turn, finally, to the Roman Empire, which can not only shed some light on problems of typology and definition, but can also itself be illuminated when set in a world-historical, comparative context.

IV THE ROMAN EMPIRE IN COMPARATIVE PERSPECTIVE

Rome is the canonical example of the ‘ancient/agrarian/tributary/land-based’ ideal type of empire. As such, it is covered in not one but two separate chapters, each written by a volume editor: the first as part of a chapter on ancient Mediterranean city-state empires, including Athens and Carthage (Scheidel, vol. 2, ch. 5), and the second devoted to the Roman empire from beginning to end (Bang, vol. 2, ch. 9) — the longest single chapter in vol. 2 at 50 pages. Both chapters are excellent. Scheidel emphasises the structural challenges faced by apex city-states in transforming their regional hegemonies into large, tributary empires, suggesting that Rome's effective ‘institutional layering’ and incorporation of a growing periphery made it an ‘ideal type of a war machine devoted to “objectless imperialism”’ (2.154–5). Bang provides an expert overview, dividing Rome's imperial history into three stages — the ‘conquering Republic’ (2.248–55), the ‘imperial monarchy’ (2.255–69), and what he calls the ‘provincial takeover’, from the third-century crisis through the fifth century c.e. (2.270–9) — with emphasis throughout on institutions and political economy. A strong stand-alone essay with copious bibliography, it can be read with profit by specialist and non-specialist alike.

For Roman historians interested in comparative analysis, the fact that the Roman Empire has been so central both to ideas about what empires ‘are’ and to the self-definitions and even day-to-day running of subsequent empires is both a blessing and a curse: the scholarship on Rome is rich and voluminous and no one disputes Rome's status as an empire, but for specialists in what has come to be a paradigmatic case, it can be difficult to escape a sort of solipsism in which all other empires are measured against it, whether explicitly or (more treacherous) implicitly. The publication of this review in a journal dedicated to the ancient Roman world is not the only reason, therefore, that the Roman Empire warrants a sustained treatment.

In thinking about Rome comparatively, the question of its legacy is simply inescapable. What is so remarkable here is the very long history of later societies using (and abusing) the record of the Roman Empire for their own purposes. We can trace a line in collective meditation on the Roman Empire from Roman late antiquity and the collective self-fashioning of Byzantine elites to the modern European empires, especially the Spanish and the British, and from Fascist Italy (with its own imperial pretensions) up through the contemporary United States.³² Other empires have had long afterlives, too, of course. The early empires of China, for example, exercised a continuing and profound influence on the self-definition and imperial policies of subsequent Chinese dynasties.³³ What was at stake in these shared recollections was not just nostalgia, as Phiroze Vasunia makes clear in his bracing chapter on imperial memories (vol. 1, ch. 15), but action. As he puts it (drawing on Pollock 2006), ‘the comparative study of empires shows that empires become imperial, that is, empires are made, by the action of looking at older empires. Historical empires stoke the flames of aspiration as much as they hold up warnings to would-be imperialists’ (1.518). If other empires have had a similar impact on subsequent imperial systems, no empire has so consistently served as a touchstone for collective reflection on history, interstate politics and power as has the Roman Empire.³⁴

Before discussing some qualitative considerations that are inevitably shaded by Rome's peculiar legacy, let us first examine Rome comparatively by means of two metrics that can be (loosely) quantified: size and duration. ‘Size’ can refer either to territory or to population. In terms of territorial extent, the Roman Empire, at c. five million square kilometres, is not quite as huge as we are accustomed to imagine, ranking no higher than eighteenth when compared to all other empires.³⁵ But if we limit the comparison to what Scheidel calls the ‘traditional’ (i.e. ‘land-based’) empires up to 1500 c.e., then we arrive at the ‘top ten’ list in Table 1.

TABLE 1. Ten largest empires, up to 1500 c.e., measured in millions of square kilometres

The Roman Empire was a fraction of the size of the larger European colonial empires, and even of some of the Eurasian agrarian empires, but set in its (broad) historical context it certainly qualifies as one of the ‘big’ ones. That is even more true for population, the other measure of size. Here the numbers are less reliable, but working with current estimates (such as they are), and ranking empires up to 1500 c.e. not by total population size but rather by overall share of the world population — a better way to compare like with like — we find a slightly different top ten (Table 2).

TABLE 2. Ten largest empires, up to 1500 c.e., measured in percentage share of world population

The simple point here is that Rome was a ‘big’ empire (but not the biggest) in both ways of measuring size. The other quantifiable metric of imperial standing is chronological duration. This is perhaps the most difficult property of all to measure and to compare, since the start and end dates of any one ‘empire’ are usually so vague (and, up to a point, subjective). But if we limit what we call ‘the Roman Empire’ to the period from the dawn of overseas expansion after the First Punic War to the final administrative division of the empire between East and West, 241 b.c.e. to 395 c.e., that amounts to a stretch of well over 600 years — a formidable number on any reckoning.

Combining these metrics, the Roman Empire is very nearly in a category of its own. Indeed, in the context of the other premodern Eurasian empires, only the Han Dynasty — with a broadly similar territorial extent, share of overall world population and duration (202 b.c.e.–220 c.e.) — really bears comparison. Rome's canonical status as an empire of world-historical significance is unimpeachable on objective grounds.

Let us turn now to qualitative considerations. It is far beyond the scope of even a long review to attempt a comprehensive comparative analysis, but we can draw upon what OWHE has given us to think through some of the ways in which Rome was typical of all empires — always a useful corrective to the exceptionalist thinking that still shapes the discourse around the Roman Empire — and some of the ways in which it was distinctive. This will point the way to a brief conclusion on why the history of the Roman Empire, and of empires more generally, still matters (below, Section V).

We begin with the place and function of local elites within the Roman Empire. That the empire devolved much of its day-to-day administration onto the urban, wealthy, landowning elites in the provinces, in exchange for marks of imperial honour, especially Roman citizenship, and new avenues of upward mobility, is a truism.³⁶ We sometimes think of this ‘grand bargain’ as a masterstroke of Roman imperial statecraft, but what must be recognised is that it was far from unique. Indeed, it could be argued that systematic collaboration with local elites was a structural feature of premodern empires, as limits to central manpower and infrastructural capacity almost always made such collaboration the most effective way to manage multiple, distant territories. Vivid examples abound in the case studies. The West Asian precursors to Rome set the pattern, from Ur III to the Achaemenids.³⁷ Cooperation between royal courts and local agents was a standard feature of successive Chinese imperial dynasties, too, with slightly different configurations under the Han, the Tang, the Ming and the Qing, usually involving some sort of financial benefit (e.g. land grants or tax concessions) in exchange for service in the imperial administration, civil or military.³⁸ Analogous cases can be found in South Asia, where the Mughal state forged a new service elite through a rigorous educational curriculum; in the Americas, where both the Aztec and Inca rulers coopted local elites through a range of sumptuary privileges and marks of honour; and in the Russian Empire, where the private wealth of the landowning and service elite was ultimately vouchsafed by the monarch.³⁹ Most empires operated as systems of power, wealth and honour in which a finely balanced calibration of interests between central and peripheral elites was essential. The Roman case is richly documented and well known to specialists, but it should not surprise us. With a few exceptions, this was how premodern empires managed to function at all, though with some differences in the nature of the ‘bargain’ — what, in effect, was exchanged for what — that would repay further comparative study.⁴⁰

The devolution of administrative responsibility onto local communities and their ruling classes has necessary implications for the ambition, reach and depth of centralised state power in any empire. Rome was no exception. In its organisational and operational parameters, Roman imperial administration was broadly comparable to that of most other premodern empires, especially in the first two centuries c.e. The typical administrative structure, as the case studies in OWHE confirm, included (i) a clear locus of ultimate decision-making authority, usually a monarchic ruler and some version of a royal ‘court’, and (ii) an administrative elite with a range of ties, personal or status-based, to the ruler, either (iii) governing discrete territorial sub-units (‘provinces’) or (iv) commanding military forces that provided both perimeter security and internal policing, all financed by (v) revenues extracted from subject populations through a more or less stable fiscal mechanism.⁴¹ Rome ticks most of these boxes for most of its long imperial history.⁴² Within this standard repertoire of imperial rule, the key variables that shaped the nature and effectiveness of any one empire's administrative apparatus were infrastructural capacity, level of administrative manpower, degree of bureaucratic rationalisation, range of specialist expertise and quality of data-collection and record-keeping.⁴³ It is a little harder to generalise here, but on our current understanding the Roman Empire does not appear to have been an obvious outlier with respect to any one of these dimensions of imperial administration.⁴⁴

The Roman Empire was also typical with respect to imperial territoriality — but not, perhaps, in the ways that we normally assume. That the Roman empire did not control its territory in the manner of a modern nation-state — with deep, comprehensive and homogenous rule over widespread areas — is clear. Like the other empires discussed above, what we call ‘the Roman empire’ was really a large-scale network of various ‘hot spots’ — cities, military installations, resource clusters and transport hubs — all linked together in the interests of a socio-political elite. In this regard, the Roman Empire (and other large, premodern empires) was more similar to the European colonial empires than we have recognised. Consider Bayly's four-fold typology for the British Empire (2.923):

First, there was the empire of royal fortresses, sea-lanes, and islands; second, the empire of ‘white’ settlement colonies; third, the empire of direct territorial control; and, finally, the empire constituted by dependent non-European monarchies or native states.

Each of these elements finds either close parallels or loose analogues in the Roman Empire, which can also be seen as a durable fusion of legionary bases, communications corridors (and, indeed, islands), transmarine colonies and provinces that were administered directly (in principle), all surrounded up through the Trajanic period by a peripheral ring of subordinate kingdoms. Two other defining features of the European colonial empires, the long-distance channelling of material resources and the development of corporations and complex financial instruments for managing the profits, are true of the Roman Empire as well.⁴⁵ One need think only of Roman imperial mining operations, whether of precious metals or stone, or of the large-scale transfer of grain, mainly from Egypt, or of the activities of the societates publicanorum, which continued to operate well into the imperial period, to see that the Roman Empire, like its European colonial successors, rested upon the effective exploitation of widely scattered pockets of material wealth.⁴⁶ It is easier to ‘see’ the networked organisation of space when we contemplate the global, maritime empires of the modern period, but the same basic principle defined the large, land-based empires, too. In its territorial dynamics, Rome was typical of most empires, ancient and modern.⁴⁷

Equally instructive for understanding the Roman Empire are those cases in which it was not typical but distinctive — for this, too, can sharpen our historical questions and make us more alert to the potential pitfalls of using Rome as a comparative case for other empires. At the level of detail, every feature of the Roman Empire (and every other empire) was of course unique; but if we consider the empire at the system level, we can identify some more substantial ways in which it stood apart from the others. Two that seem especially significant are the empire's republican, city-state origins on the one hand, and the place of women in the public sphere on the other. Let us briefly consider each in turn.

The first thing that new students learn about the Roman Empire is that it grew from a city on the Tiber river to an empire that embraced the entire Mediterranean basin and much of its continental hinterlands. It is indeed a remarkable story, but it goes without saying that many other empires grew from small beginnings, too.⁴⁸ What makes Rome anomalous in this context is that it managed to build its empire within the institutional framework of a republican city-state. As Scheidel notes in his comparative analysis of ancient city-state empires, the combination of city-state and empire is vanishingly rare — and not just in antiquity: Venice, another Italian city-state empire (vol. 2, ch. 22), never parlayed its commercial and military strength into a large territorial state. This makes the Roman Empire distinctive, with a number of second- and third-order effects, including the anomalous nature of Roman monarchy (for centuries represented as a republican magistracy); a comparatively light taxation regime; and the centrality of citizenship as a juridical form of imperial belonging.⁴⁹ With some squinting, one might discern loose parallels for any one of these features in other empires. But the combination is unique to the Roman Empire, and it was surely the product of Rome's republican origins.

Even more striking was the visibility of Roman women in the public sphere — an important topic that is finally getting the attention it deserves. The power of the women of the Roman imperial court — their privileged access to the emperor; their central place in the empire-wide economy of favours; their wealth and public image; and their periodic role in high-level deliberations on matters of state — is a central theme of the Principate and has been much studied.⁵⁰ More recently, scholars have considered different ways in which women were deeply involved in Roman imperialism and empire, including studies on women and the Roman triumph; on women as client queens and how they helped to maintain dynastic networks in Rome's periphery; and on the activities of women as patrons in the provinces.⁵¹ We are also now more sensitive to the highly visible evidence for Roman women as public benefactors during the imperial period.⁵² Given that the urban fabric and political economy of the Roman Empire rested in large part on civic benefactions, the transfer of elite women's private wealth into the public sphere was arguably necessary for making the empire function the way it did. The Roman Empire was dominated by men, but this latest wave of scholarship is rapidly revealing that women were often in the middle of the structures and processes by means of which the empire was built and maintained.⁵³ More to the point, this scholarship suggests that women were active agents in the Roman imperial project in ways that do not seem to be paralleled in other empires. This conclusion may reflect differences in academic traditions and scholarly emphasis, of course, but at the moment it appears that Rome was rather anomalous in this respect. This was evidently an important dimension of the Roman Empire, and one that deserves continued study.

V CONCLUSION: WHERE ARE WE NOW?

Thinking about the Roman Empire comparatively prompts the question of whether or not Roman imperial history, and the history of empires more generally, matters to the world today. Any answer will hinge in part on whether we believe that we are living in a post-imperial age. That question crops up here and there in OWHE, but there is no clear answer. In the prolegomena, Bang denies that empires are ‘a thing of the past’ (1.xix). John A. Hall takes the opposite view in his chapter on the ends of empires (vol. 1, ch. 16), writing of ‘the sense of a final ending to the era of empires’ (1.534). And in the concluding chapter to the whole work (vol. 2, ch. 45), Cooper, who is more agnostic on the question of our imperial present, identifies the changing relationship between sovereignty and territory, rather than the trajectories of empires as such, as the crucial dynamic in the period after World War II.

This range of responses brings us back to the problem of definition. Some contemporary nation-states bear several of the imperial attributes that recur throughout OWHE, especially the United States, China and Russia (2.1271–2).⁵⁴ An overlapping but different set of imperial attributes characterises the supranational organisation of capital, which Michael Hardt and Antonio Negri identified as the new Empire already in 2000 — almost a past epoch, it now seems.⁵⁵ In the years since, the number and spread of global circuits of capital has only intensified, producing lopsided patterns in the distribution of global wealth. Gaping inequality is the result.⁵⁶ It goes without saying that sovereignty, territoriality and transnational capital intersect in complex and often invisible ways in this age of globalisation, sometimes in mutual opposition to one another. Indeed, Charles Maier has recently argued that the history of the twentieth and twenty-first centuries can be seen as a structural competition between what he calls ‘project-states’, both democratic and totalitarian, which have aimed to enact a range of social, economic, and political policies, and their various ‘rivals’, including ‘resource empires’ (the legacy of which continues to exacerbate global inequalities), transnational capital and transnational NGOs.⁵⁷ In light of intensifying climate change and the very real prospect of environmental collapse, it is perhaps no exaggeration to say that what is up for grabs here is nothing less than the future of the planet.⁵⁸

How the dynamic relationship between states, territories, peoples, ecologies and circuits of capital will evolve, and whether the configurations that ultimately prevail will be the ‘empires’ of the future, is still unclear. Cooper's caution on this matter is sensible: ‘It is too early to tell’ (2.1274). Despite its own embeddedness in a system of knowledge production that has some imperial attributes of its own, as suggested above, OWHE does not give the reader much reason to hope that any version of an imperial future would be anything but dark. For if the history of empire as told in OWHE has shown us anything, it is that empires not only produce and replicate hierarchy, asymmetry and inequality, but that they do so through violence and through unequal access to and exploitation of material resources for the benefit of a socio-political elite. Empires are inherently coercive and extractive, and this is the case whether they take the form of states or of transnational circuits of capital. Both forms are bad for the environment, and both are bad for human flourishing. This, in the end, is the truest ‘problem’ of empire. Like any ambitious reference work, OWHE has its limitations and blind spots in its account of empire. But it is surely the best guide we now have to this protean form of social and political organisation, and it is only through understanding its deep past and current instantiations that we can hope to plan for a genuinely post-imperial future.