Identifying immigrants to Imperial Rome using strontium isotope analysis more

ROMAN DIASPORAS ARCHAEOLOGICAL APPROACHES TO MOBILITY AND DIVERSITY IN THE ROMAN EMPIRE edited by Hella Eckardt Contributors: J. L. Barta, C. Chenery, S. Chenery, H. E. M. Cool, H. Eckardt, J. Evans, M. Fulford, P. Garnsey, R. Gowland, R. Hingley, K Killgrove, S. Leach, M. Lewis, J. Montgomery, G. Miildner, E. Nimmo, D. Noy, V. Pashley, J. Pearce, T. L. Prowse, A. M. Small, T. E. von Hunnius, & J. Webster PORTSMOUTH, RHODE ISLAND 2010 Identifying immigrants to Imperial Rome using strontium isotope analysis Kristina Killgrove Introduction Imperial Rome was the seat of a colonial force and a major pre-industrial urban center. Scholarship has long been concerned with the dissemination of Roman culture and with identifying Romans and Roman materials in the archaeological record of the provinces. Although there has been interest in Romans as migrants and, more recently, in the dialectic between the colonizer and the colonized in the provinces, the issue of immigrants com- ing to Rome has been little studied except by historical demographers. Modern theoretical discussions in anthropology, however, conceive of migration as a process in which active agents move within and between both geographic and cultural space. This concept of transnationalism allows us to investigate individual migrants' lives and identities and to situate them within a contextualized social field of migration. Anthropologists and soci- ologists have successfully used the concept of transnationalism to discuss identity and ethnicity, processes of incorporation and assimilation, and maintenance of connections to the place of origin. Further, by broadening the understanding of transnational individuals to the group level, it is possible to discuss diasporas of migrants and their formation of polyethnic communities at their destination. Epigraphical, historical and material evidence from Imperial Rome tends to be biased against slaves, the lower classes and the poor, who made up a large percentage of immigrants. One important data source for Roman migration — skeletal remains — has long been overlooked. Osteological analysis of human bones lends itself well to investigating migration as a transnational, social phenomenon because of its ability to identify individual immigrants and to reveal patterns within and between communities. This paper addresses transnationalism as it relates to questions of Roman migration by using chemical analysis to identify immigrants and osteological data to contextualize their lives. Theorising transnationalism in antiquity As defined by anthropologist Caroline Brettell,1 transnationalism is "a social process whereby migrants operate in social fields that transgress geographic, political, and cul- tural borders". Transmigrants "develop and maintain multiple relationships — familial, economic, social, organizational, religious, and political — that span [these] borders".2 The concept of transnationalism arose in the 1990s as a prominent critique of the historical- structuralist and modernist theories of migration. Modernization theory encompasses a framework in which dichotomies are used to understand migration (rural/urban, city/ country, immigrant/citizen) and is focused on the motivations of migrants. The historical- structuralist approach, on the other hand, looks at the global market, combining elements of world-systems theory and core-periphery relations to explain the structure of migra- tions.3 As the world became increasingly globalized, social scientists began to debate 1 Brettell 2008, 120. 2 Baschefrt/. 1993, 7. 3 Brettell 2008, 118-20. 158 K. Killgrove the future of nation-states and sought to address individual agency in the construction of society.4 Transnationalism was thus bound up in discussions of postmodernity and postcolonialism, with focuses on both the individual and the structure: "newly created transnational spaces are sites at which new and multiple identities are fashioned and a variety of old and new forms of power or domination are exercised".5 In the 1990s, archaeologists began resurrecting studies of migration, overlooked for decades as a result of diffusionist and functionalist thinking that oversimplified a complex social process. D. Anthony, in an article of 1990 which is still widely cited, noted that: migration has been avoided because archaeologists lack the theory and methods that might allow them to incorporate migration into the explanation of culture change, not because migration is regarded as unimportant.6 Further, he points out that modern migration studies are essential for archaeologists to understand patterned migration in the past and that, although push and pull factors are useful in understanding migration, ideological and cultural factors might be equally relevant. Migration is not a one-way street, and Anthony advocates that archaeologists use all available evidence, including material culture, the literary record and biological remains, to address research questions.7 In archaeology, we are now seeing transnationalism adopted as a theoretical back- ground to migration primarily in the form of diaspora studies. Although originally a term that denoted the forced movement of ethnic groups of individuals from their home- land, diaspora has recently been re-conceived as a more metaphorical and inclusive term. R. Sanjek8 feels that diaspora "occurs when people voluntarily leave their home area for distant regions within or beyond the state in which they reside, and continue to remain in contact in various ways with their point of origin", a definition that is based on transnational theories about community.9 Diaspora can be caused by forced movement of individuals, but also by trade, labor and ideology, and often results in heterogeneous communities at the destination, variously termed polyethnic communities, transnational communities, diaspora communities,"1 or diasporic pluralism." The redefinition of diaspora, and the recognition that modern models of migration can be applied to the past, have caused a veritable paradigm shift in archaeological thought about inter-regional interaction. Yet archaeological studies are still focused on the group level, asking questions about why groups of people migrated and how groups of people assimilated or maintained a group identity. The next step in approaching ancient migra- tion through transnationalism is to attempt to understand the individual migrant, to situate the immigrant and his or her lived experiences within a community and within a culture as a whole. New techniques in bioarchaeology allow us to find the biological remains of individual immigrants, investigate changes at various times in their lives, and 4 Click Schiller i'/ al. 1995. 5 Szanton Blanc el al. 1995, 684. 6 Anthony 1990, 895. 7 An thony 1990 a nd 1997. s Sanjek 2003, 323. 9 Brettell 2008, 121. 10 Sanjek 2003; Lilley 2004 and 2006. 11 Appadurai 1996. Identifying immigrants to Rome using strontium isotope analysis 159 view individuals within the context of the community.12 There is a dialectical quality to this sort of research, as an individual skeleton is interesting for the unique set of informa- tion it can yield, but only by placing that individual within a mosaic of individuals can we interpret the patterns, similarities and differences seen. Bioarchaeology, then, allows us to ask and answer questions about migrants at different scales, from the individual to the group to the larger community. Transnationalism in Imperial Rome Imperial Rome is a suitable venue to undertake a pilot study of transnationalism in antiquity.13 Physical mobility has been called a "culturally contingent determinant of what it meant to be 'Roman'",14 because inter-regional interactions of people created and main- tained the empire. The vast literary record means that, even if individual immigrants arc- few and far between, a great deal is known about the sociopolitical structure that informs questions of transnationalism. The size of Rome under the F.mpire was unparalleled in Europe until after the Industrial Revolution, and waves of immigrants are known to have flowed into the city. In addition, the change in burial practice to inhumation means that thousands of skeletons are available for statistical and chemical analysis.15 By the early 1st c. A.D., Rome was the largest pre-industrial city in Europe, but the precise size and composition of the population is still debated. Within the walls, the estimates range from 500,000 to one million inhabitants, with an additional 500,000 to 750,000 living in the sub- urbium, an extension of the city itself and a liminal area between city and countryside.1" The Early Empire marked a growth spurt in the population. Slavery, military campaigns, trade and voluntary migration doubtless contributed to the dramatic increase in the city's population.17 By the 3rd c, the army had built a vast transportation infrastructure that stretched out across Europe, and maritime activities circulated goods and people around the Mediterranean. The image of Roman culture was propagated throughout the empire by means of coinage, building programs and the visual language of art.ls The infrastructure and ideology of the empire allowed people living far from central Italy lo have informa- tion about the urban center. The Edict of Caracalla granted Roman citizenship to all free residents of the empire. With many transportation and cultural barriers removed, it is reasonable to suppose that people were immigrating voluntarily to Rome, perhaps drawn by the promise of economic betterment. In his introduction to Foreigner* at Rome,19 D. Noy 12 I5uikstra 2006. 13 this paper arises from dissertation research on mobility and migration among the lower classes of Imperial Rome. Using skeletal remains as the data set, three main topics of inquiry were pursued: 1. changes to the fabric of Roman society as a result of migration, integration and hetero-geneous communities — which can be studied through strontium, oxygen and statisti- cal analyses; 2. differences in the economic situation for immigrants — which can be studied through carbon and nitrogen isotope analyses reflecting diet choice; and 3. how the environment in terms of health, disease and ecology affected immigrants — which can be studied through analysis of skeletal and dental pathologies. The full data can be found in Killgrove 2010. 14 Scheidel 2004, 26. is Catalano 2001; Catalano et at. 2001. 16 Wiseman 1969; Hopkins 1978; Champlin 1982; Storey 1997; Scheidel 2001 and 2004; Wircher 2005. 17 Morley 1996; Anthony 1997; Noy 2000; Scheidel 2001; Lo Cascio 2006; Paine and Storey 2006. is Zanker 1990. 19 Noy 2000. [(.I) K. Killgrove points out that the role of immigrants in the composition of the city is barely touched on in texts such as J. E. Stambaugh's The ancient Roman city.20 Scholarship on migration to Rome is mostly the work of historical demographers who debate the systemic causes for Rome's population increase in different time periods.21 The social causes and results of these immi- grations to Rome have traditionally been the field of philologists and epigraphers, but the lack of much information about lower-class and poor immigrants hampers an understand- ing of the complexities of migration to Rome. Noy attempted to engage multiple lines of evidence in investigating migration to Rome.22 The immigrant population in Rome would have been at its highest in the 3rd c. A.D. when, according to him, c.5% of the entire population was composed of free immi- grants, both soldiers and civilians of all social classes, as well as men and women, young and old, and families and individuals.23 Four general types of migration probably existed in the empire: a) local, which includes rural-to-urban movements within the peninsula; b) circular, often practiced by agricultural or domestic workers; c) chain, in which migrants encourage other migrants to move; and d) career, when a person moves in order to derive long-term economic benefits.24 The 'pull factors' of Rome were largely economic and related to work or educational opportunities, while general 'push factors', such as war and famine, could have induced individuals to leave their homelands for Rome.2:1 Noy wishes to overcome the problems with identifying individual immigrants in order to understand why they came to Rome, how they constructed their identities, and what their lives were like in the city.26 He recognizes that literary and epigraphic evidence privileges some groups (soldiers and the wealthy) and excludes others (the poor and illiterate).27 Of potentially c.50,000 free immigrants at Rome in the High Empire, only a handful would be individually identifiable as immi- grants based on a tombstone. Because techniques of chemical analysis in bioarchaeology can identify individuals who moved, they have the potential to find people not repre- sented in the epigraphic record. Noy is further concerned with ethnic representation and community identity among foreigners at Rome.28 The problem is that immigrants might have pursued a "strategy of integration":2'' "it is possible to look for signs that foreigners at Rome tried to preserve their separate identity, but much harder to look for signs that they did not".30 Individuals who integrated with Roman culture would not necessarily be seen in the archaeological record through their form of burial or grave goods, but they might be uncovered by being identi- fied biologically as immigrants while identified culturally as Romans. 2ii Stambaugh 1988. 21 E.g., Morley 2003; Jongman 2003; Scheidel 2C03; Lo Cascio 2006; Paine and Storey 2006. 22 Noy 2000 and above in this volume. 23 Noy 2000, 19 and 26. 24 Ibid. 53-55; after Tilly 1978. 25 Ibid. 86-90. 26 Ibid. x. 27 Ibid. 5. 28 Ibid. 197. 2" Ibid. 10. 30 Ibid. 160. Identifying immigrants to Rome using strontium isotope analysis 161 Identifying and understanding migration to Rome is a multidisciplinary undertaking but one that has the potential to change the way we think of immigration and immigrants in the Roman empire. Here I will lay out the results of a bioarchaeological case study of skeletons from two Rome cemeteries and their contribution to migration studies. Finding immigrants in Imperial Rome In this study of migration among Rome's lower classes, three questions are of primary importance: • Is there evidence of non-local or immigrant individuals within the population? Because of the lack of archaeological and epigraphical material in lower-class burials, chemical analyses are necessary to identify migrants. • Is there any patterning by age or sex of individuals identified as non-local? It has been suggested that younger males between the ages of 15 and 30 were more likely to immi- grate because of their service in the military.31 • What kinds of immigration strategies were pursued by migrants: local, circular, chain, career, or a combination? Bioarchaeologists typically employ non-destructive statistical techniques, destructive chemical analyses, or a combination thereof, on human skeletal and dental remains to answer these kinds of questions. Materials In his de Legibus,32 Cicero notes that the Twelve Tables specifically forbade both burying and cremating the dead within the city: hominem mortuum in urbe nesepelito neve urito. The Roman suburbium was therefore used for marginal businesses excluded from the city for religious or public safety reasons; they included slaughterhouses, brickmaking facilities, and cemeteries.33 No matter where an inhabitant of Rome lived, that person would almost certainly end up in a cemetery outside the walls, in the periurban or suburban area. In 2007, I analysed human skeletal remains from over 180 individuals from two sites, Casal Bertone and Castellaccio Europarco, both in Rome's suburbium, at the labora- tory facilities of the Soprintendenza Archeologica di Roma (fig. 9.1).31 Casal Berlone is a modern neighborhood less than 2 km from the city walls. Public works projects since 2000 have revealed a villa, part of a Roman road, a nymphaeum, a cemetery with mausoleum, and a large (1,000 m2) industrial complex35 which Italian archaeologists believe is a ful- lery or tannery of the 2nd-3rd c. A.D. A total of 138 individuals were examined, 38 from a mausoleum and 100 from a necropolis. Sex and age were assessed through standard bio- archaeological methods.31' More male (n=54) than female individuals (n=24) were found. The average age at death of adults is in the 31-40 year-old range.37 Castellaccio Europarco 31 Paine and Storey 2006, 76. 32 Cic, de Leg. 2.23.58. 33 Toynbee 1971; Purcell 1987; Champlin 1982. "•4 For additional information about the lead concentrations and isotope ratios of the Casal Bertone and Castellaccio Europarco populations, see Montgomery el a\. below in this volume. 35 Musco et al. 2008. 36 Buikstra and Ubelaker 1994. 37 Killgrove2010, chapt. 4. 162 K. Killgrove Fig. 9.1. Imperial Roman cemeteries mentioned in the text (adapted from a map of the modern ring road and ancient walls by (i. lirueggeman). includes a necropolis situated in the sub- urbium along the via Laurentina. Ongoing excavations since 2004 have brought to light the road, a bridge, two villas and hydraulic works that helped prevent the Tiber from flooding.38 Masonry technique, artifacts and an inscription dating to A.D. 177 point to three phases at this site: 4th- 3rd c. B.C., 2nd-1st c. B.C. and lst-2nd c. A.D. Skeletons were found in each phase. A total of 45 were examined from the latest period. Among adults, more males (n=24) than females (n=7) were found. The aver- age age at death is in the 31-40 year-old range. A variety of characteristics reflects the diversity of the individuals buried at these sites. Although their demographic profiles are similar, Castellaccio Europarco has a higher incidence of disease processes such as carious lesions, porotic hyperostosis and cri- bra orbitalia. Its burials were more diverse in form than those at Casal Bertone, possibly indicating differences in the wealth, status, or origin of the people. Castellaccio Europarco lay at an important crossroads where migrants may have settled. The large industrial complex at Casal Bertone perhaps employed foreigners. All burials at these sites were simple, many in the a cappuccino (tile-covered) style, and nearly all lacked grave goods. Methods The most useful chemical methods for studying ancient migration are isotope analy- ses of the ratios of 87Sr/s,,Sr and l80/"'0 present in the human body. The oxygen isotope ratio of both meteoric and environmental water (rain, snow; rivers, springs, lakes) varies by region in relation to factors such as temperature, humidity, distance from the coast, latitude, rainfall and elevation.39 Oxygen is incorporated into the body through the inges- tion of water and food, as well as the inspiration of air. Strontium isotope ratios, on the other hand, are related to bedrock and the geological peculiarities of a particular region. As bedrock weathers, it releases strontium into groundwater and surrounding soil, and this element is incorporated into the human body during tissue formation. Chemical analysis of human skeletal remains can thus indicate whether an individual moved during his or her lifetime, and potentially even the area from which the person came. Several isotopic studies have been carried out to investigate migration in antiquity using both oxygen411 and strontium,41 but the study by T. Prowse et al. is the only isotope analysis of migration to have been performed in central Italy for the Roman Imperial 3s BuavlUo 201)7; Buceellato el al. 2008. 39 Craig 1961; Gat 1996. jo Dupras <-f nl. 2001; Evans <•/ al. 2006; Prowse et al. 2007. 11 Buzon el al. 2007; Montgomery et al. 2005; Schweissing and Grupe 2003. Identifying immigrants to Rome using strontium isotope analysis 163 period. Comparisons in oxygen isotope ratios between paired first and third molars indi- cated that a large number of migrants came to Portus as children.42 It was not possible for the researchers to pinpoint immigrants' places of origin because of the imprecision of iso- topic gradients, but there is clear evidence that men, women and children immigrated to Portus in the Imperial period. Although there are data on the oxygen isotope ratios of meteoric water in Italy, the entirety of the Tyrrhenian coast is undifferentiated, meaning it is impossible to tell, using oxygen isotopes alone, if an individual originated at Rome or at any other location along the W coast of Italy.43 Whereas oxygen isotope ratios vary roughly E to W, strontium isotope ratios vary roughly N to S owing to the volcanic geology of a large part of the peninsula.44 Studying migration in Imperial Rome therefore necessitates both strontium and oxygen isotopes to characterize ancient mobility. In this paper I report on the immi- grants identified through strontium isotope analysis and attempt to contextuali/.e their lives. Publication of the entirety of the strontium results combined with an oxygen isotope analysis of a subset of the population is available in my dissertation.45 One non-pathological first molar was extracted from every skeleton at Casal Bertone (n=79) and Castellaccio Europarco (n=26) which possessed at least one of these teeth. Although osseous tissue remodels and regenerates throughout the lifetime of an individ- ual, teeth do not remodel following amelogenesis and eruption — they only wear down. The permanent first molar begins forming shortly after birth, and the crown is complete around the age of three.46 The isotope ratio measured from the permanent first molar, then, represents an average over the first three years of an individual's life. At the Isotope Geo- chemistry Laboratory of the University of North Carolina, Chapel Hill, dental enamel was extracted from 105 ultrasonically-cleaned, sectioned first molars using a Brasseler hand- held dental drill fitted with a round carbide bit. Strontium was extracted from the samples and measured using the protocols and standards given in M. Perry el ai.47 Since no other strontium isotope analyses have been performed to date on human skel- etal remains from ancient Italy, understanding the bioavailability of strontium at Rome is difficult. Based on strontium isotope analysis of volcanic samples from the Alban Hills complex, the s7Sr/s,'Sr ratio of Rome consists of a range from .7090 to .7103.4H However, Rome was importing a significant portion of its drinking water through aqueducts that tapped springs in the pre-Apennines. Strontium ratios measured at springs in the Monti Simbruini near the source of several ancient aqueducts yield values in the range of .7079 to .7080.49 The strontium ratio (.7092) of seawater and rainwater probably contributed to the strontium ratios of both humans and animals as well. Based on a mixing model that takes into account the lower strontium isotope values of aqueduct water and the higher 42 For a recent discussion of the article by 1'rowse et al., see C. Bruiin's article in IRA 2.1 (2010) and my subsequent response. 43 Longinelli and Selmo 2003. 44 Turi and Taylor 1976. 4^ Killgrove2010. 46 Hillson 1996. 47 Perry etal. 2008,540-41. 48 Ferrara el al. 1985; Federico el al. 1994. 4>i Barbieri and Sappa 1997. 164 K. Killgrove strontium isotope values of the volcanic geology, a local strontium isotope range for the geology of Rome and the suburbium may be estimated conservatively at .7079 to .7103.50 Mammals process strontium from both water and food sources, however, meaning that biological strontium ratios can represent a slightly different range than that obtained from geological material. Lacking further data on the bioavailability of strontium with which to refine the strontium isotope range characteristic of Rome and its suburbium, here I take a necessarily conservative approach and identify only clearly anomalous individuals as immigrants. Of the 105 individuals analysed, 7 were identified as significantly different isotopically from the local range of Rome: 2 (7.7%) from Castellaccio Europarco and 5 (6.3%) from Casal Bertone. These figures are slightly higher than Noy's estimate of 5% immigration at the height of the empire.51 A visual presentation is given in the form of a dot histo- gram of all strontium ratios measured (fig. 9.2). Black dots represent non-local individuals whose strontium ratios are 2 standard deviations (95% CI) from the overall mean. Grey dots represent non-local individuals with strontium ratios 1.645 standard deviations (90% CI) from the mean. Non-local individuals are identified by their skeleton numbers to facili- tate further discussion.52 oo ooo ooo ooo ooo oooo oo ooooc oooooc o ooooo oooooooococ 3oooaooococ A vV Or Qy Fig. 9.2. Dot histogram of'^Sr/^'Sr ratios. ET16T8 Tr. TABLE 9.1 DEMOGRAPHICS OF IMMIGRANTS Castellaccio Europarco Casal Bertone ID ET76 ET38 T8 T36 T15 T24 T72 Sex A%e Height (cm) Burial sli/le M M M M 11-15 41-50 170 7-9 14-16 31-40 51-60 11-15 175 assente assente piana in anfbra piana pinna assente Contextualising immigrants Following the identification of possible immigrants, it becomes possible to investigate migrants in comparison with the population as a whole. By placing individuals in relation 50 For a full explanation of this model, see Killgrove 2010. 51 Noy 2000. 52 Individual T72 presented a strontium isotope value at the lower border line of the Roman range and is cautiously interpreted here as an immigrant: see Killgrove 2010 for further discussion. Identifying immigrants to Rome using strontium isotope analysis 165 to others in their own community as well as other communities across the empire, we will be able to begin to piece together the lived experiences of immigrants. Castellaccio Europarco The burials at Castellaccio Europarco were not arranged in a particular cemetery or necropolis context, but were often made at the base of or close to structural features such as walls flanking the via Laureniina?7, Four main burial styles were identified by the excavators: • a cappiiccina or tegola (a burial covered by vaulted or flat tiles); • in anfora or in coppa (a burial in a ceramic vessel); • assente (lack of burial covering); and • blocchi basalti (burials at the base of a wall). The vast majority were simple, lacking any covering (75%). A handful were tile burials and burials of subadults in amphorae or other pottery vessels. Based on the strontium results, two outliers represent a lower and a higher strontium value than typically found in Rome. ET76 was a probable male who was about 15 years old at the time of death. This mostly complete skeleton had no noted postcranial pathologies and only a little dental calculus. ET38 was a male in his 40s who stood 170 cm tall, the average for a male in this population. There was evidence of degenerative changes in his mid-back and hips, but these are normal in middle age. His dental health was quite good, with only slight calculus build-up on his anterior teeth and a few ante-mortem chips. He had bilateral rhomboid fossae, indicative of a strong costoclavicular ligament attachment (fig. 9.3).54 He had probably engaged in repeated and forceful movement of both arms. Both were males who came to Rome some time after three years of age. With only two immigrants identified at Castellaccio Europarco, it is difficult at this point to find patterns in the associated osteological data. Fig. 9.3. Bilateral rhomboid fossae. Caslellaceio F.uroparco. FT38. Casal Bertone Casal Bertone consisted of two burial locations: an above-ground mausoleum that housed loculi with multiple skeletons in each, and a nearby necropolis. The mausoleum slightly postdates the necropolis as its foundations were built atop several graves. Within the necropolis, the excavators noted 4 types of burials: • a cappiiccina (covered by a vaulted tile structure); • piana (covered by a flat tile structure); • assente (no covering); and • in anfora (burial within an amphora). 53 Buccellatocf al. 2008. 54 Hawkey and Merbs 1995. 166 K. Killgrove The majority of burials (57%) in the necropolis had either a cappuccino or plana style tile- coverings, while 35% lacked a covering and about 8% (only subadults) were found in amphorae. Based on the strontium results, the 5 anomalous individuals represent three values lower and two higher than Rome. All identified immigrants come from the necropolis of Casal Bertone (5 out of 57, or 9%). No skeleton (0 out of 23) from the mausoleum had an anomalous strontium signature. Individuals in the mausoleum might have been of slightly higher social class than those in the necropolis, possibly even members of a collegium asso- ciated with the nearby fullery or tannery. Burials in both mausoleum and necropolis covered all age ranges and both sexes. The non-local individuals consist of three subadults and two adult males. T36 represents an adolescent of about 14-16 years (sex unknown). Although the teeth were in reasonable condition, there is evidence of healing cribra orbitalia on the skull and of periostitis on the legs, indicating physical stress from a poor diet or disease. Evidence of a strong conoid ligament attachment on the right clavicle indicates that this young adult probably engaged in forceful or vigorous back-and-forth movement of the right arm on a repeated basis (as, e.g., in rowing or swinging a stick to beat cloth).55 Of all the amphora burials, T36 is the oldest individual; most amphora burials at both Casal Bertone and Castellaccio Europarco are of children under 5 years of age. T8 was a child of about 7-9 years of age. While this child's skeletal health was reason- able, there were carious lesions in the baby teeth, a dental abscess that led to loss of another deciduous molar (fig. 9.4), and extensive destruction and remodeling of the alveolar bone. T72 was an adolescent between 11 and 13 years old at the time of death. The enamel hypoplasias on all four of the canines suggest a systemic physical stress event (possibly dietary or disease-related) around the age of three and a half. 55 Ibid. Identifying immigrants to Rome using strontium isotope analysis 167 T24 was a male in his 50s who stood about 175 cm tall (a little over the male average at this site). He had multiple sites of arthritis in his feet and lower jaw, evidence of a healed fracture in his right hand (fifth metacarpal: fig. 9.5) and signs of possible use of his teeth in a repetitive action. There was considerable ante-mortem tooth loss and a healing dental abscess. T15, a male in his 30s, has the most divergent strontium ratio. He had quite a few areas of bony deformity as a result of either arthritis or trauma sustained to the left hip and left elbow. His mid- to lower back had bony lipping of the vertebral bodies and Schmorl's nodes, indicative of possible disc herniation. On his right ulna there was a strong brachialis muscle attachment, indicating repeated elbow flexion (as seen, e.g., in lifting heavy objects with the arms).56 In his dentition there was evidence of ante-mortem tooth loss, carious lesions, calculus and chipping. Assessing origins In order to work out where non-local individuals originated, it is necessary to define the lithologies in the area where an individual obtained his or her food and water. I he anoma- lous strontium ratios in this study are both lower and higher than the local area of Rome. The higher individuals, ET38 and T15, probably lived in an area with older Palaeozoic rock such as granite. This type of rock is sparse in the Italian peninsula, the only large outcrop- pings being found in Calabria and NE Sicily.57 Older granitic rocks are also found in the Alps of Germany and Switzerland,58 as well as in a large outcrop on the F. wast of Corsica. Based on strontium signatures, all these are possible homelands for individuals F.T38 and T15, but oxygen isotope data''1' suggest that a N Italian origin in l.iguria or Tuscany is most likely. The two individuals (ET76 and T8) whose strontium ratios are slightly higher than the local Roman signature probably lived in an area with a geological signature higher than that of the volcanic area of Rome. Published strontium isotope data of the volcanic areas north of Rome (Monte Vico, Monti Sabatini and the Tuscan magmatic area) all give ratios slightly higher than Rome.60 ET76 and T8 have statistically higher strontium ratios than the individuals identified as local and were probably short-distance immigrants to Rome. Individuals with a lower strontium ratio than Rome include T36, T72 and T24. A lower strontium ratio means that an individual was obtaining water from younger geology such as volcanic rock or carbonate. The geology of Rome is anomalous, ranging from c. .7090 to .7103, despite its composition of young volcanic rock. Other volcanic areas include Vesuvius, Monte Vulture in south-central Italy, Etna in Sicily and the W coast of Corsica. Pockets of sandstone and limestone, which tend to have lower strontium values, dot the peninsula. Measured strontium isotope ratios from most of these contexts demonstrate lower numbers than the Roman volcanic region/'1 As above, oxygen isotope data for these individuals help narrow down their probable homelands: T24 might have come from the 5(> Ibid. 57 Servizio Geologica d'ltalia 2004. 58 Faure and Powell 1972. 59 Killgrove2010, chapt. 9. wi Turi and Taylor 1976; Avanzinelli et al. 2008. hi ISarberi et al. 1969; Turi and Taylor 1976; Pennisi el ill. 2000; Barbieri and Mororti 2003; Avanzi- nelli et al. 2008. 168 K. Killgrove Apennines, T72 from a geographical area similar to Calabria, and T36 from a region iso- topically similar to N Africa.62 Using the criteria established to approximate the strontium range of Rome and its suburbiuiu, 7 out of 105 individuals were found to be non-local. Pinpointing immigrants' homelands using only strontium is difficult since the geology of an area does not necessarily translate directly to the strontium signature of a human tooth. If we make the conservative assumption that most immigrants to Rome came from the Italian peninsula, it is likely that the immigrants identified here came from areas such as Liguria, Tuscany, Lazio, the Apen- nines, Calabria and Africa. Bodies of (migrant) work Prowse et al.'s oxygen isotope study at Portus found that men, women and children were immigrants. The strontium results from the present study similarly confirm that some men immigrated to Rome after the age of three, and there is evidence of children immigrat- ing to Rome after age three but before the age of majority, but neither Casal Bertone nor Castellaccio Europarco has produced clear evidence of women as immigrants. It is unsur- prising that 4 of the 7 individuals with anomalous strontium ratios are men, as men were more mobile due to occupations that forced them to travel (e.g., soldier or merchant). It is unclear if the children came to Rome with their families, as slaves or on their own. As it is impossible visually to determine sex from subadult remains, it is not known if the chil- dren were male or female. Most immigrants to the city appear to have come from areas relatively local to Rome in a rural-to-urban move sometimes called centripetal migration,63 and at least two individuals in the isotopically-identified immigrant population came from a considerable distance, possibly as career migration. Although there are no comparative strontium data from ancient Italy, several researchers have published information on pathological conditions in skeletal populations contempo- raneous with those at Casal Bertone and Castellaccio Europarco, namely, from Vallerano/'4 Quadrella,65 Portus,66 Lucus Feroniae,67 Vagnari/* Herculaneum,69 Pompeii711 and Urbino.71 These sites date to the Imperial period but are distributed throughout the peninsula, some being urban settlements, some rural. The most comparative data to come out of these projects include dental pathologies (carious lesions and linear enamel hypoplasia) and cranial pathologies (porotic hyperostosis and cribra orbitalia).72 If we contextualise the populations of Casal Bertone and Castellaccio Europarco and their immigrants, for the most part the individuals from Rome appear to be healthier than their counterparts in the peninsula, with lower frequencies of carious lesions and linear enamel hypoplasias, as well 62 Killgrove 2010, chapt. 10. 63 Scheidel 2004, 14. 64 Ricci et at. 1997; Cucina et at. 2006. 65 Bonfiglioli et al. 2003; Brasili et al. 2004; Belcastro et al. 2007. 66 Prowse 2001. 67 Sperduti 1997; Manzi el al. 1999; Salvadei et al. 2001. 68 Prowse 2008. 69 Bisel1991. 70 I lenneberg et al. 1996. 71 Vargiu et al. 2007; Paine et al. 2009. 72 See also Cowland and Garnsey above in this volume. Identifying immigrants to Rome using strontium isotope analysis IM as lower Frequencies of cribra orbitalia. Individuals at both study sites have lower overall frequencies of linear enamel hypoplasias as compared to the other urban sites (I lercula- neum, I'ompeii, Portus). ' Based on ,1 tew basic osteological indicators ol health, il appears that individuals from the two study sites overall were subject to fewer physical and envi- ronmental stressors, such as malnutrition and infectious disease, than individuals from around the peninsula. This is possibly the result of good access to clean water in the city and suburbium?* The pathologies of individual immigrants from the study sites, however, tell a slightly different story. Skeletal lesions on I S, 172 and 136 suggest these adolescents were either sick or were not being fed properly over sufficient stretches of time to cause bony and dental lesions. Both adult males (124 and 115) similarly had poor cental health compared to the remainder of the Casal Bertone population. Three (T36, T24, T15) of the four Casal Bertone immigrants show traumatic injuries and exostoses that indicate they engaged in physical labor throughout much of their lives. Evidence of muscle overuse was found in the upper bodies of these individuals, indicating repeated lifting and swinging motions. As the Casal Bertone cemetery was located near a large industrial area (fullery or tannery), it is possible the men and children worked there.75 Discussion The first step in assessing immigration to Rome — namely, finding individual immi- grants — can be accomplished w ith chemical analyses of human skeletal remains. Further work is planned to characterize the bioavailability of strontium in Rome given the com- plex geology of the region and heavy reliance on aqueduct water and imported food in the Imperial period, but the preliminary strontium isotope results presented above do show outliers in the data set indicative of non-local individuals. In comparing these non-local individuals to the rest of the population, it appears that immigrants were not as healthy as locals. In addition, evidence was found suggestive of both short- and long-distance move- ment among subadults and adult males, but not among adult females. Further research questions will be raised as this project progresses in order to understand more fully the phenomenon of migration and the lives of migrants in the Roman empire. Theories of transnationalism frame my research questions in terms of identity, ethnicity and agency .mil in ways thai can be addressed by looking ,il the bioarchaeological data from the two study sites and other Roman skeletal populations. Identity Transnationalism involves migrants who transgress traditional boundaries and create and maintain relationships that span these borders. In the modern world, anthropologists are interested in migrants' economic ties to their homeland, in whether they send money to family back home or own property in different nations. Although the pre-industrial world probably did not allow for such events, soldiers and their families stationed away wrote 73 74 75 Killgrove 2008 and 2010, chapt. 5. Killgmve 2008. Bradley 2002. 170 K. Killgrove letters home,76 and people could send and receive money while away from home.77 Two questions that can be asked of bioarchaeological data include: • Did the transmigrant move only once, multiple times, or in a cyclical manner away from and then back to his or her homeland? • Did the transmigrant maintain cultural ties to his or her homeland while living else- where? It is possible to investigate the first question using strontium or oxygen studies of an individual at several points during his or her life by testing teeth that form at different ages. The second question is often approached archaeologically through material cul- ture or burial style, but that method would not pick up an individual who tried, or was made, to assimilate with the host culture. One method of investigating cultural ties is by an analysis of habitual actions (e.g., unique methods of manufacturing an object). The skel- eton constantly remodels to accommodate the actions of muscles and joints (whereas it does not remodel dental wear). Specific patterns of movement could indicate retention of traditional methods of, e.g., spinning or leatherworking. Another method of investigating cultural ties is the use of carbon and nitrogen stable isotope ratios that serve as an indicator of an individual's diet. Lack of evidence of dietary change in a transmigrant could indicate maintenance of traditional foodways and his or her identity. The results of the carbon and nitrogen isotope analysis of the Castellaccio Europarco and Casal Bertone skeletons sug- gest that some immigrants acculturated to a Roman-style diet after arriving in the city.78 Ethnicity Transmigrants operate within a community, and the composition of that community is also of interest anthropologically. Transnational spaces in contemporary anthropology involve areas where transmigrants can construct multiple or situational identities. A Mexi- can transmigrant to the U.S.A., for example, probably has differing identities in his or her Spanish-speaking home and English-language school. More concretely, transmigrants exist physically within a geographic space or ethnoscape; the ethnic construction of that community is of interest to the anthropologist.74 We can ask questions such as: • Did transmigrants from the same homeland live in geographic proximity in homo- geneous communities in the host country? • Did transmigrants live in polyethnic communities, heterogeneous in composition yet still separate from the local inhabitants? • Were transmigrant communities dispersed throughout the city or were they located on the fringes? Through a combination of strontium and oxygen isotope studies, we may be able to iden- tity the approximate geographical origin of transmigrants living in polyethnic communities and understand the way individuals in these communities chose to display or conceal their ethnicity. Structure and agency Finally, transmigrants and polyethnic communities operate within a larger socio-political structure. It is at this level that we can start engaging questions of transmigrant agency: 76 Bowman 1998, 82. 77 Andreau l999, 20-21. 78 Killgrove 2010, chapt. 11. 79 Appadurai 1996. Identifying immigrants to Rome using strontium isotope analysis I /1 • What was the consensus about immigrants in the host culture? • How did the transmigrant react to the socio-political context — by complete cultural assimilation, by maintenance of traditional ways, or somewhere in between? • Did female transmigrants react differently than males? • Were upper- and lower-class transmigrants treated differently? It is no accident that these questions return us to the experiences of individual trans- migrants, for "migrants act and are 'acted upon' with reference to their social, cultural, and gendered locations"80 — that is, there is a dialectic of agency and structure, and both the individual and the structure are important for understanding the social process of trans- nationalism. Conclusions While not a panacea, strontium isotope analysis can begin to provide insights into ques- tions of migration to Imperial Rome. This study has produced clear evidence of migrants to Rome, individuals who moved from another geographic locale after the age of three and were buried in cemeteries near the city. Archaeological context by itself does not permit identification of these individuals, who were buried in a standard, lower-class fashion with no indication that they had been born elsewhere. Evidence from these two cemeteries indi- cates that most of the migration was short-distance or centripetal, possibly in the form of rural-to-urban movement in search of economic betterment for individuals and their fami- lies, or possibly related to slavery. The combination of strontium ratios with osteological data indicates more males than females immigrated to Rome in these two populations but also that children immigrated. Many of the migrants appear to have engaged in manual labor which caused repeated stress injuries to their skeletons, and many were sickly or malnourished compared to the rest of the population. Strontium isotope ratios are pre- cise chemical signatures in teeth, but mapping them to a geographical area is not a perfect science, since the geology of Italy is complex and individuals ingest strontium from a vari- ety of sources. The combination of strontium and oxygen isotope analysis provides a more thorough method of identifying anomalous individuals and their homelands.Hl Approaching migration in Imperial Rome from a transnational perspective and com- bining the available evidence are beginning to allow us to see migrants to Rome in a way that has been impossible before. The potential for a study of identity, ethnicity, memory and agency of migrants in Rome is unparalleled because of all the material and historical evidence available to help formulate questions and test hypotheses. Bioarchaeo- logical approaches can provide evidence of the social phenomenon of migration both synchronically and diachronically at multiple levels of interaction: individuals, families, communities, the empire and even within one individual's lifespan. Transnationalism and diaspora are new ways of conceiving of migration in antiquity and will help give voice to individual migrants as agents within a social structure who helped create, maintain and negotiate their role in a polyethnic society. Acknowledgments This research would not have been possible without grants from the National Science Foundation (BCS-0622452), the Wenner-Gren Foundation, and the Research Laboratories of Archaeology, the so Brertell 2008, 136. 81 Killgrove 2010, chapt. 10. 172 K. Killgrove Graduate School, and the Center for Global Initiatives all at the University of North Carolina, in sup- port of my dissertation project. Strontium analysis was performed with the help of D. Coleman and I'. Fullagar of the Department of Geological Sciences at UNC. Access to the skeletons and permis- sion to take samples from Casal Bertone and Castellaccio Europarco were granted by P. Catalano, director of the Anthropology Service of the Soprintenden/a Archeologica di Roma. This paper was greatly improved by the comments of two anonymous reviewers. Any errors or omissions are, of course, my own. References Anderson, 15. 1983. Imagined communities (London). Andreau, J. 1999. Banking and business in the Roman world (Cambridge). Anthony, D. 1990. "Migration in archeology: the baby and the bathwater," American Anthropologist 92, 895-914. Anthony, D. 1997. "Prehistoric migration as social process," in J. Chapman and H. Hamerow (edd.), Migrations and invasions in archaeological explanation (BAR S664, Oxford) 21-32. Appadurai, A. 1996. Modernity at large: cultural dimensions of globalization (Minneapolis, MN). Avanzinelli, R., T. Elliott, S. Tommasini and S. Conticelli 2008. "Constraints on the genesis of potassium-rich Italian volcanic rocks from U/Th disequilibrium," /. Petrology 49,195-223. Barberi, F., S. Borsi, C. Ferrara and F. Innocenti 1969. "Strontium isotopic composition of some recent basic volcanites of the southern Tyrrhenian Sea and Sicily Channel," Contributions to Mineralogy and Petrology 23.157-72. Barbieri, M. and M. Morotti 2003. "Hydrogeochemistry and strontium isotopes of spring and mineral waters from Monte Vulture volcano, Italy," Applied Geochemistry 18, 117-25. Barbieri, M. and G.Sappa 1997. "Application of geochemical and isotopic analysis methods (S/Sr/s<'Sr) in hydrogeological characterization of some springs in Simbruini Mountains (Italy)," in 1. Yil- ma/.er (ed.), Proc. Int. Symposium on Geology and Environment (Istanbul) 77-81. Basch, L., N. Click Schiller and C. Szanton Blanc 1993. Nations unbound: transnational projects, post- colonial predicaments, and deterritorialized nation-states (Basel). Belcastro, G. el al. 2007. "Continuity or discontinuity of the life-style in central Italy during the Roman Imperial age-early Middle Ages transition: diet, health, and behavior," Am. ). Phys. Anth. 132,381-94. Bisel, C. 1991. "The human skeletons of Herculaneum," Int. \. Anth. 6,1-20. Bonfiglioli, B., I'. Brasili and M. Belcastro 2003. "Dento-alveolar lesions and nutritional habits of a Roman Imperial-age population (lst-4th c. A.D.): Quadrella (Molise, Italy)," Homo 54, 36-56. Bowman, A. 1998. Life and letters on the Roman frontier: Vindolanda and its people (London). Bradley, M. 2002. '"It all comes out in the wash': looking harder at the Roman fullonica," jRA 15, 20-44. Brasili, I'., E. Bianchi and A. Ventrella 2004. "Traumatic events and life-style in ancient Italian popu- lations," Collegium Anthropologicum 28, 179-91. Brettell, C. 2008. "Theorizing migration in anthropology," in C. Bretell and I. Hollifield (edd.), Migration theory: talking across disciplines (London) 113-60. Buccellato, A. 2007. "L'antica via Laurentina: Tarteria e le infrastructure," FASTI Online 88. Buccellato, A., P. Catalano and W. Pantano 2008. "La site et la necropole de Castellaccio," Les dossiers d'archiologie 330,14-19. Buikstra, J. 2006. "Introduction: on to the 21 st century," in J. Buikstra and L. Beck (edd.), Bioarchaeology: the contextual analysis of human remains (Burlington, MA) 347-58. Buikstra, J. and D. Ubelaker 1994. Standards for data collection from human skeletal remains (Favetteville, AR). Buzon, M., A. Simonetti and R. Creaser2007. "Migration in the Nile Valley during the New Kingdom period: a preliminary strontium isotope study," }ArchSci 34,1391-401. Catalano, I'. 2001. "Bioarcheologia. Archivio antropologico," in F. Filippi (ed.), Archeologia e Giubileo. Gli intervenli a Roma e nel Lazio net piano del Grande Giubileo del 2000 (Naples) 123. Catalano, P., S. Minozzi and W. Pantano 2001. "Le necropoli romane di eta imperiale: un contributo all'interpretazione del popolamento e della qualita della vita nell'antica Roma," Atiante tematico di topografia antica 10,127-38. Champlin, E. 1982. "The suburbium of Rome," A]AH 7, 97-117. Craig, 11. 1961. "Isotopic variations in meteoric waters," Science 133,1702-3. Identifying immigrants to Rome using strontium isotope analysis 173 Cucina, A. et al. 2006. "The necropolis of Vallerano (Rome, 2nd-3rd century A.D.): an anthropological perspective on the ancient Romans in the suburbiutn," Int. /. Osteoarchaeology 16, 104-17. Dupras, T., H. Schwarcz and S. Fairgrieve 2001. "Infant feeding and weaning practices in Roman Egypt," Am. ). Phys. Anth. 115, 204-12. Edwards, C. and G. Woolf (edd.) 2003. Rome the cosnwpolis (Cambridge) Evans, J., N. Stoodley and C. Chenery 2006. "A strontium and oxygen isotope assessment of a possi- ble fourth-century immigrant population in a I lampshire cemetery, southern England," lArchSci 33, 265-72. Faure, G. and J. Powell 1972. Strontium isotope geology (New York). Federico, M., A. Peccerillo, M. Barbieri and T. Wu 1994. "Mineralogical and geochemical study of granular xenoliths from the Alban Hills volcano, central Italy: bearing on evolutionary processes in potassic magma chambers," Contributions to Mineralogy ami Petrology 115, 384-401. Ferrara, G. et al. 1985. "Oxygen and strontium isotope studies of K-rich volcanic rocks from the Alban Hills, Italy," Earth and Planetary Science Letters 75,13-28. Gat, J. 1996. "Oxygen and hydrogen isotopes in the hydrologic cycle," Annual Review of Earth and Planetary Sciences 24, 225-62. Click Schiller, N., L. Basch and C. Szanton Blanc 1995. "From immigrant to transmigrant: theorizing transnational migration," Anthropological Quarterly 68, 48-63. Hawkey, I), and C. Merbs 1995. "Activity-induced musculoskeletal stress markers (MSM) and sub- sistence strategy changes among Hudson Bay Eskimos," /)//. /. Osteoarchaeology 5, 324-38. Henneberg, M., R. Henneberg and A. Ciarallo 1996. "Skeletal material from the house of C. lulius Polybius in Pompeii, 79 A.D.," Human Evolution 11, 249-59. I lillson, S. 1996. Dental anthropology (Cambridge). I lopkins, K. 1978. Conquerors and slaves (Cambridge). Jongman, W. 2003. "Slavery and the growth of Rome: the transformation of Italy in the second and first centuries B.C.E.," in Edwards and Woolf 2003,100-22. Killgrove, K. 2008. "Slums or suburbs? Health status of a population from Imperial Rome," Am. /. Phys. Anth. 135, Suppl. 46,129. Killgrove, K. 2010. Migration and mobility in Imperial Home (Ph.D. diss., Univ. of North Carolina at Chapel Hill). Lilley, I. 2004. "Diaspora and identity in archaeology: moving beyond the Black Atlantic," in L. Meskell and R. Preucel (edd.), A companion to social archaeology (Oxford) 287-312. Lilley, I. 2006. "Archaeology, diaspora and decolonization," /. Social Archaeology 6, 28-47. Lo Cascio, E. 2006. "Did the population of Rome reproduce itself?," in Storey 2006, 52-68. Longinelli, A. and E. Selmo 2003. "Isotopic composition of precipitation in Italy: a first overall map," /. Hydrology 270, 75-88. Manzi, G., L. Salvadei, A. Vienna and P. Passarello 1999. "Discontinuity of life conditions at the transition from the Roman Imperial age to the early Middle Ages: example from central Italy evaluated by pathological dento-alveolar lesions," Am. \. Human Biology 11, 327-41. Montgomery, J., J. Evans, D. Povvlesland and C. Roberts 2005. "Continuity or colonization in Anglo- Saxon England? Isotope evidence for mobility, subsistence practice, and status at West Heslerton," Am. /. Phys. Anth. 126,123-38. Moi ley, N. 1996. Metropolis and hinterland: the city of Rome and the Italian economy 200 B.C.-A.D. 200 (Cambridge). Morley, N. 2003. "Migration and metropolis," in Edwards and Woolf 2003, 147-57. Musco, S. et al. 2008. "Le complexe archeologique de Casal Bertone," Les dossiers d'archeoloyie 330, 32-39. Noy, D. 2000. Foreig)iers at Rome: citizens and strangers (London). Paine, R. and G. Storey 2006. "Epidemics, age at death, and mortality in ancient Rome," in Storey 2006, 69-85. Paine, R., R. Vargiu, C. Signoretti and A. Coppa 2009. "A health assessment for Imperial Roman buri- als recovered from the necropolis of San Donato and Bivio CH," /. Anth. Sci. 87,193-210. Pennisi, M. et al. 2000. "Boron, Sr, O, and H isotope geochemistry of groundwaters from Mt. Etna (Sicily) — hydrologic implications," Geochimica et Cosmochimica Acta 64, 961-74. Perry, M., D. Coleman and N. Delhopital 2008. "Mobility and exile at 2nd century A.D. Khirbet edh- Dharih: strontium isotope analysis of human migration in western Jordan," Geoarchaeology 23, 528-49. 174 K. Killgrove Prowse, I. 2(H)I. Isotopic and denial evidence for diet from the necropolis of Isola Sacra <lst-3rd centuries A.D.), Italy (Ph.D. diss., McMaster Univ., Ont). Prowse, T. 2()I)<S. "I.ilo and labor on an Imperial Roman estate," Archaeological Institute of America 109th Annual Meeting Abstracts, 31. Prowse, T. ct al. 20114. "Isotonic paleodiet studies of skeletons from the Imperial Roman-age cemetery ol Isola Sacra, Rome, Italy," lArchSci il, 259-72. Prowse, T. el al. 2007. "Isotopic evidence for age-related immigration to Imperial Rome," Am. /. P/it/s. Anth. 132, 510-19. Purcell, N. 1987. "Tomb and suburb," in H. von Hesberg and P. Zanker (edd.), Rbmische Graber- strasseu: Selbstdaistellung, Status, Standard (Munich) 25-41. Ricci, R. <•/ al. 1997. "Pattern of porotic hyperostosis and quality of life in a II century A.D. farm near Rome," Rh'ista di Anlropologia 75, 117-28. Salvadei, I.., I'. Ricci and G. Man/i 2001. "Porotic hyperostosis as a marker of health and nutritional conditions during childhood: studies at the transition between Imperial Rome and the early Middle Ages," Am. /. Human Biology 13, 709-17. Sanjek, R. 2003. "Rethinking migration, ancient to future," Global Networks 3, 315-36. Scheidel, W. 2001. "Progress and problems in Roman demography," in id. (ed.), Debating Roman demography (Leiden) 1-82. Scheidel, W. 2003. "(terms for Rome," in Edwards and Woolf 2003,158-76. Scheidel, W. 2004. "Human mobility in Roman Italy, I: the free population," jRS 94,1-26. Schweissing, M. and G. Grupe 2003. "Stable strontium isotopes in human teeth and bone: a key to migration events of the I.ate Roman period in Bavaria," JArchSci 30, 1373-83. Servizio Geologica d'ltalia 2004. Geological map of Italy, 1 : 1,250,000 scale (32r.d Int. Geological Congress). Sperduti, A. 1997. "I ife conditions of a Roman Imperial-age population: occupational stress markers and working activities in Lin us leroniae (Rome, lst-2nd cent. AD)," Human Ei'olution 12, 253-67. Stambaugh, J. 1988. The ancient Roman city (Baltimore, MD). Storey, G. 1997. "The population of ancient Rome," Antiquity 71, 966-78. Storey, G. (ed.) 2006. Urbanism in the preindustrial world: cross-cultural approaches ( Tuscaloosa, AL). S/anton Blanc, C, L. Basch, and N. Click Schiller 1995. "Transnationalism, nation-states, and cul ture," Current Anthropology 36, 683-86. I ilk, C. 1978. "1 he historical study of vital processes," in id. (ed.), Historical studies of changing fertil- ity (Princeton, NJ) 3-56. I ovnbee,). M. C. 1971. Death and burial in the Roman world (London). Turi, B. and 11. Taylor 1976. "Oxygen isotope studies of potassic volcanic rocks of the Roman province, central Italy," Contributions to Mineralogy and Petrology 55, 1-31. Vargiu, R., R. Paine, C. Signoretti and A. Coppa 2007. "A paleopathologies! assessment of Impe- rial Roman burials excavated from the necropoli of San Donato and Bivio CI I, Urbino, Italy," Am. /. Phys. Anth. 132, Suppl. 44, 237. Wiseman, T. 1969. " The census in the first century B.C.," IRS 59, 59-75. Witcher, R. 2005. " The extended metropolis: urbs, suburbium, and population," IRA 18, 120-38. /anker, P. 1990. I'he power of images in the age of Augustus (Ann Arbor, Ml).