Princeton/Stanford Working Papers in Classics The demography of Roman state formation in Italy Version 1.0 November 2005 Walter Scheidel Stanford University Abstract: This paper seeks to provide a basic demographic framework for the study of integrative processes in Italy during the Republican period. Following a brief summary of the state of the debate about population size, the paper focuses on distributional issues such as military and political participation rates and geographical mobility, and concludes with a simple model of the dynamics of Italian integration. © Walter Scheidel. [email protected] Introduction1 Between the 390s and the 260s BCE, the Roman state grew from a city-state into a complex, multi-layered system of domination that claimed either direct control or indirect hegemony over the entire Italian peninsula. This complexity persisted until the mass enfranchisements of the 80s BCE. From the 260s BCE onwards, this region became the core of a tributary empire with a penumbra of client states that gradually extended across the Mediterranean basin. This expansion precipitated massive social and economic change in that core, including the centripetal accumulation and concentration of capital stocks, accelerating urbanization and mass migration, and the creation of a slave economy. At the same time, the main political institutions of the original city-state that had already been in place by the early fourth century BCE remained essentially unchanged. Demographic features are of critical significance for our understanding of these concurrent but partially divergent lines of development: any assessment of the direction and broader significance of particular trends requires some appreciation of their scale and distribution in relation to the affected population. In this paper, I present a basic demographic framework for the study of integrative processes in Italy during the Republican period. After a brief summary of the state of the debate about population size and a look at the intractable problem of demographic structure, I focus on distributional issues such as military and political participation rates and geographical mobility, and conclude with a simple model of the dynamics of Italian integration. I must stress at the outset that nothing in this outline is based on ‘hard’ statistical data. Reliable quantifiable evidence for this period is impossible to come by: reported figures need not be accurate or are sufficiently ambiguous to support (sometimes dramatically) different interpretations. Moreover, such records as do exist are limited to a relatively narrow slice of the overall demographic experience of ancient Italy such as army strengths and the scale of colonization schemes, and much of what we need to know – or, at least, need to have some rough idea of – in order to appreciate the nature of crucial features is simply not covered at all in our sources. Probabilistic estimates that are derived from ancient data, as well as general considerations of plausibility sustained by comparative historical information, are the only remedies for these severe shortcomings. At best, this approach yields tentative impressions of likely orders of magnitude and the scale and direction of change. Thus, whenever seemingly ‘precise’ figures are proffered in the following sections, they merely represent notional means with wide margins of uncertainty. Yet notwithstanding these inherent deficiencies, alternative strategies pose even greater hazards. Outright agnosticism in the face of insufficient evidence, the obvious alternative to probabilistic estimates and parametric modeling, would deny us the opportunity to make explicit and probe the logical corollaries of the ubiquitous implicit assumptions that govern more traditional scholarship. We can never hope to judge the meaning of conventional qualifiers such as ‘large’, ‘common’ or ‘important’ unless we gain at least a vague idea of the appropriate orders of magnitude and the relative weight of particular variables. For this purpose, the present survey aims to combine previous scholarship on demographic issues with my own more recent work on Roman demography and ongoing research on ancient state formation. 1 This paper was prepared for the international conference ‘Herrschaft ohne Integration? Rom und Italien in republikanischer Zeit’, organized by Martin Jehne and Rene Pfeilschifter in Dresden (Germany) in October 2004. It will be published in the proceedings of the conference. 2 Population size and structure Any modern assessment of military mobilization and political participation rates is necessarily governed by our understanding of overall population number. First published in 1971, Brunt’s massive study of Italian manpower established a de facto consensus on the demographic history of Republican Italy that more recent critiques have failed to invalidate.2 For much of the Republican period, the internal consistency of the surviving census tallies leaves little room for doubt: tallies of between 260,000 and 400,000 civium capita between the beginning of the third century and the end of the second century BCE support a credible scenario of a gradual expansion of the citizenry through enfranchisement and natural growth.3 On the assumption that these figures encompassed all male citizens over the age of seventeen, they point to a total citizen population that increased from about 800,000 to 1.3 million individuals, or somewhat more if we allow for some degree of underregistration.4 The size of the allied populations is empirically unknown for the entire period. As I have argued elsewhere, Polybius’ breakdown of allied manpower in 225 BCE, which has commonly been employed to estimate overall allied population strength, may well be fatally compromised by contemporary extrapolation from known to unknown quantities.5 Even so, given what we know about the relative size and quality of the ager Romanus and the allied territories, we may surmise that the combined allied populations outnumbered the Roman citizenry by approximately two to one (or rather, initially by more than two and later by less). This suggests a free population of perhaps 3 to 3.5 million in peninsular Italy for much of the Republican period.6 This estimate, in turn, tallies well with Beloch and Brunt’s interpretation of the (much higher) Augustan and Claudian census figures as pertaining to citizens of both sexes and all ages. Since most of the four to six million citizens reported between 28 BCE and 47 CE (and probably to be adjusted to closer to five to seven million to control for moderate levels of – historically common – underregistration) must have resided in Italy, this reading implies broad continuity over time.7 However, the fact that these readings are mutually consistent does not prove that they are correct. Indeed, a rival ‘high population’ scenario in which earlier census counts were confined to iuniores and/or assidui, and the early monarchical tallies included adult men only, requires the same small number of starting assumptions (i.e., two) as the ‘low’ estimate championed by 2 2 P. A. BRUNT, Italian Manpower 225 B.C.-A.D. 14, Oxford 1987 , reinforcing and (vastly) elaborating the major arguments about Roman population size advanced by J. BELOCH, Die Bevölkerung der griechisch- römischen Welt, Leipzig 1886. For criticism, see below, n. 7. 3 See BRUNT (n. 1), 26-83 for discussion. The general tenor of this sequence is consistent with Polybius’ (II 24) reference to 273,000 adult male citizens in 225 BCE. 4 I use a multiplier of 3.175 to account for younger men and all women following the predictions of Model West Level 3 Females (r=0) in A. J. COALE / P. DEMENY, Regional Model Life Tables and Stable Populations, New York2 1983, 57. Comparable models would not significantly affect the outcome, and the limited representative value of model life tables (see below, at n. 10) in any case keeps us from attaining anything even remotely approaching precision. 5 See W. SCHEIDEL, Human Mobility in Roman Italy, I: The Free Population, JRS 94 (2004), 1-26, at 3-4, on Polyb. II 24, a passage that contains no fewer than four suspiciously round ratios of Roman to allied manpower that are unlikely to be the result of chance. 6 SCHEIDEL (n. 4), 4-5, 9 n. 57. For earlier attempts to determine allied and overall Italian population size in 225 BCE, cf. esp. A. AFZELIUS, Die römische Eroberung Italiens (340-264 v. Chr.), Copenhagen 1942, 98- 135, and BRUNT (n. 1), 44-60, who rely on a combination of Polybius’ tableau and comparative data on carrying capacity. 7 Scheidel (n. 4), 9. The demographic gains produced by the enfranchisement of transpadane Gaul in 49 BCE would likely have been offset by massive emigration and the growing impact of urban excess mortality (ibid. 9 n. 57). This long-term stability of free population number and its beneficial consequences are key elements of my forthcoming re-interpretation of social and economic conditions in late Republican Italy: W. SCHEIDEL, The ‘Golden Age’ of Roman Italy, in progress. 3 Brunt.8 Since all of these starting assumptions are to some extent controversial and ultimately unverifiable, no amount of debate over their relative merits will ever decide the argument. The main weakness of the ‘high’ count lies in the fact that it logically predicts a mid-imperial gross population of Italy of close to 20 million, a tally three times as high as that implied by the ‘low’ count and extremely implausible for a number of reasons that I have discussed in greater detail elsewhere, including its mismatch with comparative data from other parts of the Roman empire and from later historical periods, its implications regarding the size and distribution of the imperial population as a whole, and its logical incompatibility with well-documented developments such as the emergence of a central Italian slave economy and the eventual peripherization of military service.9 In brief, thanks to the nature of the evidence, a genuinely conclusive reconstruction of Roman population numbers in Republican Italy will forever remain out of reach.