The past decade has seen a flurry of books on the Constitutio Antoniniana (Caracalla’s universal grant of Roman citizenship, henceforth the CA), many of them prompted by its anniversary in 2012. Arnaud Besson’s monograph is the most ambitious in conception, aiming at a sweeping re-assessment of its effects. Besson assumes, surely rightly, that we cannot hope to judge the impact of the CA without understanding the significance of Roman citizenship both before and after the grant itself. Hence the book becomes a survey of Roman citizenship over a period of more than four centuries. This necessarily entails a degree of selectivity in the subject matter, but the lines of enquiry are well chosen to support Besson’s key conclusions, namely that the CA represented a rupture from earlier imperial policy and that its most significant effects were in the family sphere, mediated by the Roman law of marriage, status and succession.
Part I (‘Sources’) begins with a careful review of all the well-known direct evidence for the CA, from Cassius Dio to the famous fragment of the edict itself on P. Giss 40. The unsurprising conclusion is that they have little of substance to tell us. There follows an extensive discussion of the problem of dating the CA. The highlight is an excellent, up-to-date discussion of the proliferation of Aurelii across the empire and their implications for the date of the CA. Worthy of particular note is the analysis of the frequency of Aurelii in Egyptian papyri datable by year, which increases from an average of 1.5 per year in 208-211 to 5 in 212 and then 12 in 213 and 10 in 214. (The uptick as early as 212 is interesting, though Besson is reluctant to attribute it to the CA). The evidence suggests that the edict had been announced in Asia by March 213 at the latest, in Egypt by early June and Achaia by the summer. Besson concludes that it must have been promulgated in Rome some time in 212, plausibly in the first half of the year. Given the extensive discussion of P. Giss 40 earlier (32-45), it is perhaps a pity that there is no discussion of Peter van Minnen’s provocative new suggestion that the papyrus contains two texts not three, and hence that the CA is in fact precisely dated on the papyrus (to 11 July 212) – the most important intervention on the subject since Peter Hermann’s publication of the Lydian epitaph dating to March 213.
Part II (‘Grants’) surveys the avenues by which peregrines could become Roman citizens, distinguishing between ‘personal’ and ‘collective’ grants. The latter category includes the manumission of slaves, grants to soldiers and veterans and the promotion of magistrates in communities with the Latin right, on the grounds that they all operated quasi automatically. The key conclusion of the discussion of the various forms of ‘collective’ grant is that the rate of grants was likely to slow over time. The section on personal grants focuses particularly on the evidence for the documentation of enfranchisement and the policing of citizen status. Particular attention is paid to Pliny’s correspondence with Trajan, the Tabula Banasitana and the epikrisis procedure in Egypt. Besson concludes that grants of Roman citizenship were tightly controlled and required the support of powerful patrons. The overall thrust of Part II is to suggest that Caracalla’s grant was a radical departure from earlier practice.
Part III (‘Conflict of laws’) tackles the complex question of the relationship between the Roman state and non-Roman legal institutions, offering a synthesis of the formidable specialist bibliography on the subject, going back to Ludwig Mitteis’ foundational Reichsrecht und Volksrecht. Besson sketches the situation of legal pluralism that prevailed both before and after the CA, covering first norms and then jurisdictions. The discussion of legal norms shows that Roman authorities had always accepted the validity of most non-Roman norms and continued to do so for centuries after the CA. The only area where something like a personality principle can be observed – that is, a requirement that Roman citizens use Roman law – is the sphere of family law, to which Besson returns in Part IV. The rest of Part III takes up the plurality of jurisdictions, showing that local courts continued to exist alongside the jurisdiction of provincial governors even after 212. If there was a trend towards legal homogenisation, it was a long-term process to which the CA was only one contributing factor.
Part IV (‘Exclusive institutions’) turns to the area where Besson thinks the CA did have marked effects, namely family law. But first comes a discussion of personal status, showing that Roman citizenship was not universal even after 212. There were still slaves, freed slaves, including some who were not Roman citizens (the Junian Latins and dediticii), and ‘barbarians’ who were excluded from Roman citizenship. Then follows a longer discussion of several exclusive institutions in Roman family law. The Roman law of marriage was generally prejudicious to marriages between Roman citizens and peregrines, making it difficult to transmit citizen status to the children of mixed marriages. Meanwhile, the Roman law of succession prevented Roman citizens from bequeathing property to peregrines. Besson argues that one of the most important effects of the CA would have been to remove these obstacles to intermarriage and to the flow of capital through inheritance.
The nature of the project makes this fundamentally a work of synthesis. Its originality lies in the combination of subjects often discussed separately rather than the novelty of individual arguments. There certainly are numerous new contributions on various points of detail, such as the argument that Caracalla abolished immunity from the inheritance tax for close kin in the case of intestate succession (349-52). But the overall value of the book lies in its work of integration. This is an impressive achievement since it requires command of several difficult literatures and a diverse range of evidence.
Besson is surely right that the CA had some of its most significant effects in the sphere of the family, by virtue of the relatively strict personality principle that seems to have applied in the domains of marriage, status and succession. One could debate the scope of these effects in provincial society. The rules about the transmission of status and property only became meaningful in the case of litigation before a Roman authority or an encounter with the fiscal administration. They must have mattered principally for the propertied classes and may have been largely irrelevant for much of the population. One could also point to other potentially important aspects of the experience of Roman citizenship that fall outside the scope of Besson’s study, such as identity or cult. But that is just to say that even this sweeping survey cannot cover everything. Besson offers an excellent account of the effects of Roman citizenship in general, and the CA in particular, in the legal sphere.
Like all first books, this has its origins in a dissertation, and the genre remains visible in its structure, particularly in the extensive presentation of evidence as a prelude to analysis. This can result in a degree of inconcinnity between the significance of an issue and the attention it receives. It is somewhat odd that, for example, the book devotes as much space to describing P. Giss. 40 and the problems it raises (32-45), on which it has nothing new to say, as is does to the topic of the treatment of mixed unions in Roman law (304-16) – though the latter is central to Besson’s understanding of the impact of the CA. The most important ideas and arguments tend to be concentrated in relatively short sections of the text, particularly in the elegant and very useful conclusions at the end of each chapter. Readers might benefit from reading these sections first, and then dipping into the sections that precede them.
This volume will be a useful first port of call for scholars interested in various aspects of Roman citizenship in the imperial period. It takes its place alongside Valerio Marotta’s recent overview of Roman citizenship in the imperial period as a helpful introduction to a range of complex issues with sprawling, specialist bibliographies. Readers can be sure to find a judicious and up-to-date discussion of many topics, including an overview of the principal evidence and references to recent literature. Its usefulness is greatly enhanced by the excellent summaries at the end of each chapter, the indices, and extensive cross-referencing.
 Barbara Pferdehirt and Markus Scholz, Bürgerrecht und Krise. Die Constitutio Antoniniana 212 n. Chr. und ihre innenpolitischen Folgen (Mainz, 2012); Armando Torrent, La Constitutio Antoniniana: reflexiones sobre el papiro Giessen 40 I (Madrid, 2012); Chiara Corbo, Constitutio Antoniniana. Ius philosophia religio (Naples, 2013); Clifford Ando, Citizenship and Empire in Europe 200-1900 (Stuttgart, 2016); Alex Imrie, The Antonine Constitution (Leiden, 2018).
 Peter Van Minnen, ‘Three Edicts of Caracalla? A New Reading of P. Giss. 40’, Chiron 46 (2016), 205-21 (cited in Besson’s bibliography, but not discussed). Peter Herrmann, ‘Überlegungen zur Datierung der Constitutio Antoniniana’, Chiron 2 (1972), 519–30.
 Ludwig Mitteis, Reichsrecht und Volksrecht in den östlichen Provinzen des römischen Kaiserreichs. Mit Beiträgen zur Kenntniss des griechischen Rechts und der Spätrömischen Rechtsentwicklung (Leipzig, 1891).
 Valerio Marotta, La cittadinanza romana in età imperiale (secoli I-III d.C.) (Turin, 2009).