Elio Lo Cascio and Laurens E. Tacoma's edited volume joins the array of publications on mobility in the Roman world that have emerged over the last twenty-five years. The study of Roman mobility is notoriously difficult, given that sources usually deny us numbers from which to wring statistical meaning. We often find ourselves speaking of the Roman Empire as a ‘very’ mobile place, one ‘more’ so than we might have expected. Still, the integration of epigraphic, papyrological, numismatic and literary evidence, plus experimentation with anthropological and sociological methods and, in rarer cases, postcolonial criticism, has opened doors. The efforts of the past quarter-century demonstrate just how much investigators can uncover about a topic that evades the quantification that specialists of later periods can often perform. Approaches have ranged from the pursuit of the longue durée, such as Peregrine Horden and Nicholas Purcell's The Corrupting Sea (2000) and Claudia Moatti's ‘Translation, Migration, and Communication in the Roman Empire’, CA 25 (2006), 109–40; to the identification of the physical mechanics of travel, like Ray Laurence's The Roads of Roman Italy (1999); to the advancement to places distant from the Mediterranean, like Kasper Grønlund Evers's Worlds Apart Trading Together: The Organisation of Long-Distance Trade between Rome and India in Antiquity (2019); to the study of the hyperlocal, the subpopulation, or the individual, such as Lien Foubert's work, which manages all three. We are now significantly more enlightened than we were about how individuals, groups, local governments and the Roman state enacted, experienced, controlled and cognised movement.

And, though not all investigators working in this area have put it so frankly, identity figures ever larger in order to privilege, where possible, the mobility of refugees and exiles; the freed and enslaved; women, children and animals; and even the dead. This newer politics of mobility is a partial reflection of, on the one hand, the centrality of immigration in North American and European political discourse and the human suffering perpetuated by state-sponsored immigration caps, and on the other, a growing desire among some scholars to write histories that confront the uglier applications of Roman studies in the past and present. One hopes that this desire continues to materialise. The subject of mobility is impossible to disentangle from politics of identity and exclusion: qualification remains vital.

The present volume reflects all these currents. It consists of an introduction and twelve essays that emerged from a conference held by the Impact of Empire international research network in 2015. The contributors are Greg Woolf, Lukas de Blois, Anthony R. Birley, Peter Herz, Werner Eck, Elena Torregaray Pagola, T., Gil Gambash, Margherita Carucci, Elena Koestner, Stéphane Benoist, and Moatti. One of the volume's strengths is its diversity of subject matter, approach, and context. T.'s near-literary ‘Bones, Stones, and Monica: Isola Sacra Revisited’, for example, compares what human bones and inscriptions from Ostia's necropolis can tell us about immigration. He juxtaposes isotopic evidence with an elegant musing on the movements of women in Augustine's life, raising important questions about the logics of interpreting and reconciling different sources of evidence. In ‘The linouphoi of P.Giss. 40 II Revisited: Applying the Sociological Concept of Ethnic Colonies to Alexandria's Linen Weavers’, Koestner experiments with Friedrich Heckmann's theory about migrant self-organiszation to trace out the mechanics of Caracalla's expulsion of linen-workers from Alexandria in 215. In ‘Coloni et incolae, vingt ans après. Mobilité et identité sociales et juridiques dans le monde romain occidental’, Benoist reflects on the impact of modern concerns about immigration on modern historiography, and gives a detailed analysis of the shifts in value and conceptualisation that legal terms for categorising non-locals underwent in the West.

Another strength of the volume is the attention of several papers to how the Roman imperial state shaped the movements of its subjects and, in particular, those in its employ. In ‘Moving Peoples in the Roman Empire’, Woolf speculates on why Rome may not have engaged in large-scale deportation of peoples in the manner of other early states. Eck, in ‘Ordo Senatorius und Mobilität: Auswirkungen und Konsequenzen im Imperium Romanum’, charts the little-studied travels of senators and their families, and the impacts of that travel on local communities. Birley's ‘Viri Militares Moving from West to East in Two Crisis Years (AD 133 and 162)’ offers spectacular and rigorous microhistories of men whose military careers took them from one end of the empire to another.

Like most edited volumes, the constituent papers of The Impact of Mobility and Migration in the Roman Empire rarely speak to each other, so the resulting whole does not present a unified approach to the subject of mobility. This is not a problem. As T. points out in his paper, ‘Not only do we have to take all available sources into account, as we no doubt all aim to do, but before we start to do so and before we start to create a coherent narrative, we would do well to analyse the inconsistencies first’. Unitary approaches and readings do not produce good history.

What is problematic, however, is the absence from several papers of articulated definitions and updated frameworks of analyses appropriate to their respective scopes of study. For example, in his overview of the demographic changes that Thrace, Moesia Inferior and Dacia underwent in the third quarter of the third century c.e., de Blois unironically uses language like ‘marauding barbarians’ and ‘plundering bands’. The essay is reminiscent of the generations of scholarship that yearned for the days of Rome's ethnic purity and territorial integrity. His discussion of the subject ought to have contextualised the motivations that brought populations beyond the empire within its borders. Even the invocation of older models for mobility, such as those that think in terms of push-pull factors, or Charles Tilly's classification of types of migration, would have produced a more nuanced, well-rounded picture of the empire's fringes. In ‘The Dangers of Female Mobility in Roman Imperial Times’, Carucci looks at the Latin canon to explore the perils that travelling women faced, without engaging in the source criticism that this corpus demands. She uses its moralising trope of the female lover lost at sea as evidence that women, like men, could die in shipwrecks, without asking why it was through movement that Roman authors criticised women who left home (even if leaving was how they remained with their husbands).

Such shortcomings are, however, limited to only a few papers. On the whole, the editors have curated a volume that demonstrates where the study of Roman mobility is and the places to which it might, so to speak, go.