This is a timely book indeed. Migration, urbanization, acculturation (and its limits) have all emerged as defining issues of the early twenty-first century; so too, as Laurens Tacoma shows, these forces defined the city of Rome in the early centuries of the Principate. T.’s goal is to create a conceptual framework to supplement empirical studies such as David Noy's Foreigners at Rome (2000) and advance our understanding of the relationship between migration, urbanization and labour that shaped the imperial city. His contribution is very welcome, and scholars of immigration in the Roman world will find Moving Romans to be a stimulating addition to the field.

The book is organized into eight chapters, each helpfully divided into digestible subsections. Ch. 1, ‘Migration Before Modernity’, surveys the primary sources for migration to Rome, which include literary texts, all-important epigraphy, material culture and isotopic analysis of skeletal remains. T. notes a key problem with inscriptions: ancient people often did not express identity primarily in ethnic terms but often emphasized legal or social status instead (18). We thus risk leaving important material on the table by limiting ourselves to inscriptions in which foreign origin is directly mentioned. Without slighting Noy's groundbreaking work, which analysed approximately one thousand inscriptions from free-born immigrants to Rome, T. notes that this dataset could be expanded by a factor of ten if factors such as temporary or forced migration were considered (19). Ch. 2, ‘Conceptualizing Migration’, identifies ten types of migration and tackles the twin challenges of estimating Rome's population and determining how many immigrants lived in the city. T. cautiously settles on a figure of 20–30 per cent first-generation immigrants in a city of 800,000–1,000,000, but stresses that we should envision a flexible population that ‘breathed and changed its composition all the time’ (70, 74). Ch. 3, ‘The Roman Migration Regime’, contrasts modern migration models, which are inextricably tied to the emergence of the nation state and racial thinking, with a Roman migration policy that T. describes as liberal to the point of non-existence (75, 105). There was no such thing as migrant status in imperial Rome, so the concept of illegal immigration that dominates our current discourse was not a factor in migrants’ lives (104).

Three central chapters focus on aspects of immigrants’ lived experience. Ch. 4, ‘Migration and the Family’, concludes that most newcomers to Rome were young men between the ages of fifteen and thirty who came to the city as individuals. Female mobility primarily occurred in the context of marriage and family life, though many individual women also came to Rome as slaves. T. notes that some migrants, such as soldiers, tended to return home after living in Rome for years and warns that examining evidence only from the city itself may therefore skew our impression of the immigrant community's size (133). Ch. 5, ‘Migration and Urbanization’, examines immigration's rôle in keeping Rome's population stable. Immigration rates must have been high, since deaths brought on by poor living conditions and disease were compounded by low fertility rates among the immigrant population due to the fact that men outnumbered women (167). Ch. 6, ‘Migration and Labour’, notes that the economic boundary between slave and free labour was often blurred, and that much of our written evidence skews toward the skilled part of the labour force (185). The construction and transport industries would have provided a living for thousands of unskilled day labourers who are largely invisible in the sources. While shared origin or common ethnicity could help certain immigrants find work, such as traders who sold goods associated with certain regions, most would have had to create new patronage networks or enter into existing ones (201).

The final chapters address questions of immigrant community. In ch. 7, ‘Migration and Acculturation’, T. argues that ties among immigrants were relatively weak, and that only in rare cases (such as the Jews) is it possible to distinguish migrant communities based around shared origin, language, work or worship (206, 230). The cluster of dedications to eastern deities associated with the Sanctuary of Bel near the Porta Portuensis and the Syrian Sanctuary on the Janiculum, for example, does not prove the existence of a sharply bounded community of Syrian transplants in Rome. T. notes that the term ‘Syrian’ masks a diversity of origins and backgrounds, and is right to argue that comparing temples of eastern gods in Rome to ethnically strong churches that serve as focal points for immigrant communities in some modern societies is misleadingly anachronistic (224). Still, it is hard to imagine that the longevity of such institutions, their accessibility to jobs for newly arrived migrants on the Tiber docks, and their proximity to the Jewish community established in Trastevere since the first century b.c. does not point to some degree of clustering among immigrants from Syria and the Levant in south-western Rome during the Principate. T. is right to say that there was ‘no automatic community formation along ethnic lines’, yet as he admits in his concluding chapter, ‘migration surely led to a culmination of affiliations’ (246, 266). Immigrant community at Rome was likely more about intersections and connections than about clear boundaries between groups. To those who wish to investigate these connections at the level of street, shop or insula, T.’s work will be an invaluable resource.