09— Paleobiology of early medieval populations from the northeast of Trás-os-Montes (Portugal)

09— TERESO: Paleobiology of early medieval populations���

09— Paleobiology of early medieval populations

from the northeast of Trás-os-Montes (Portugal)

Sofia TERESO1

(CIAS|UC; IEM|NOVA FCSH)

abstRact

The paleobiological study of the early medieval populations that lived between the Tua/Tuela and Douro rivers gains a significance in the Portuguese archaeological context, contributing to the knowledge of this period in the northeast of Trás-os-Montes. In this project, we approach the ways in which communities organized their funerary space, the architecture of their graves and the funerary rituals they adopted. Their lifestyles, the biological profile of each individual, pathologies, occupational patterns, diet and mobility throughout their lives will also be characterized. In addition to the study of life and death, social distinctions within and between these communities will also be examined.

KeywoRds

Paleobiology, early medieval burials, paleodiet, population mobility, Trás-os-Montes.

1� Introduction

The early peninsular ecclesiastical provinces roughly traced the Roman provincial divisions that resulted from the Diocletian reform. The dioceses that made up the five Hispanic ecclesiastical provinces changed in number until the 8th century. Episcopal surveillance was limited to areas that were largely defined by the bishop’s ability to establish relationships with local elites, relationships that depended on the benefits that they would see in this connection (David 1947; Díaz 2011).

The region under analysis is located between the rivers Tua / Tuela and Douro (Northeast of Trás-os-Montes, Portugal), a territory on the border between the ecclesiastical provinces of Lusitania and Galecia and the dioceses of Braga, Viseu, Lamego and Caliabria after the 7th century and consequently some distance away from any episcopal see (Alarcão 2015; Tente 2016).

The Parochiale Suevum (AD 572–582) allows an approach to Suevic diocesan organization and should be seen as a list of churches that were under the direct jurisdiction of the dioceses (Díaz 2011). Only one of these parochial churches can be located in the study area: Brigantia. Brigantia was dependent on Braga and recent research has identified it with the site of Castro de Avelãs (Bragança) (André et al.

2014; Tereso et al. 2015). However, we know that some cemeteries do not appear to be associated with churches. Crestelos and Laranjal seem to be examples of this. These two cemeteries were discovered and excavated during the archaeological impact minimization works for the Baixo Sabor Hydroelectric Dam (Pereira et al. 2015; Santos et al. 2016;).

1 PhD-FCT (SFRH/BD/116363/2016)

143

PARTE II— Territorios en transición y creación de nuevos paisajes All five cemeteries in our study —Torre Velha, Quinta de Crestelos West and East, Laranjal and Mós—, have human osteological remains preserved, which is extraordinary due to the geology of the region (granite and schist). With preserved bones, we can develop an interdisciplinary study that goes far beyond the merely formal analysis of cemeteries, following the European research agenda. These multidisciplinary approaches, combining archaeology with anthropology and chemistry allow us to obtain concrete data about life and death in medieval communities. With stable isotope analysis we can reconstruct population mobility and diet (Bentley 2006; Stallo et al. 2008).

Since the beginning of the 20th century, the early medieval period has been seen as a time of migration during which exogenous populations, seen as Germanic, arrived in the Iberian Peninsula. Their material expression could be seen in grave goods considered exogenous to the late Roman world (Palol Salellas 1956; Almeida 1962). Strontium stable isotopes analyses used in projects in other areas of the Iberian Peninsula has reduced the scale of migration but allowed us to identify social differentiation between individuals from the same community (Quirós Castillo et al. 2013).

2� Material

The human remains under study were exhumed from five early Medieval cemeteries in the district of Bragança, northeast region of Trás-os-Montes: Torre Velha (Castro de Avelãs, Bragança), Laranjal, Crestelos Este, Crestelos Oeste and Mós (Torre de Moncorvo, Bragança) (Figure 1).

These cemeteries have all their origin in the Early Middle Ages (5th–9th centuries) and were reused throughout Middle Age (until the 14th century). The sample has a total of 317 individuals, 177 in primary context and 140 belonging to ossuaries. As shown in Table 1, Laranjal presents the highest number of graves (n=201) and individuals in primary (n=103) and secondary contexts (minimum number of individuals [mni] = 93).

Individuals in primary

Individuals in secondary

Cemeteries

Chronology

Graves

(centuries AD)

(N)

context

context

(N)

(mni)

Torre Velha

(Castro de Avelãs)

6th-13th

59

39

17

Laranjal

(Torre de Moncorvo)

6th-13th

201

103

93

Quinta de Crestelos Este

(Torre de Moncorvo)

8th-13th

33

15

19

Quinta de Crestelos

Oeste

5th-7th

56

5

0

(Torre de Moncorvo)

Mós

(Torre de Moncorvo)

9th-14th

39

15

11

Total

n=388

n=177

n=140

Table 1: Data about the human samples in the study.

144

09— TERESO: Paleobiology of early medieval populations...

Figure 1: Geographic locations of the cemeteries in the study.

3� Objectives and methodological approaches

Multidisciplinary analysis allows the reconstruction of ancient communities. Early medieval documentary sources are scarce and insufficient to understand the everyday life of communities.

Therefore, bioanthropological studies and the application of new methods – such as stable isotopes analysis (for inferences about diet and mobility) and genetics, combined with archaeology and the interpretation of historical data have become a crucial source for the knowledge of past societies.

145

PARTE II— Territorios en transición y creación de nuevos paisajes

Figure 2: Graves from Torre Velha

(Castro de Avelãs).

Figure 3: Congenital disease:

Spina bifida occulta.

Laranjal, Burial nº 160.

146

09— TERESO: Paleobiology of early medieval populations...

3.1. Funerary practices

Analysis of the funerary practices of the communities is based on the archaeological excavation record.

It is important to characterize the funerary area and each grave spatially (Vigil-Escalera Guirado 2013).

Therefore, it is essential to classify the space in which the cemetery is located, if is urban or rural and its type (community, familiar or private). Both urban and rural have features that distinguish them in the funerary context (Arezes 2014). Next, the internal organization of each cemetery, the architecture of the graves (type, dimensions, shape, materials used in their composition) (Figure 2), the burial position and orientation, and presence or absence of grave goods should be described. Finally, comes their classification in one of the groups traditionally defined as post-imperial, Visigothic, or Hispano-Visigothic (Vigil-Escalera 2013).

3.2. Paleobiological analysis

Taphonomic analysis is particularly important to evaluate the preservation of human remains. It studies the processes that affect the body after death (Ferreira 2012). Taphonomic phenomena result from different conditions of corpse decomposition and the intervention of natural agents in the grave: erosion, concretion, physical-chemical changes and the activity of microorganisms, fauna, flora or even man (Ferreira 2012). Therefore, all macroscopically observable changes should be recorded and described, so that we can assess the effect/impact of taphonomic factors on the skeletal sample.

Population demography will be analysed to establish a minimum number of individuals (mni). In order to obtain a complete biological profile of each individual under study, we need to analyse sex, age at death, stature, robustness and non-metric variants in bones and teeth. For that, we will use the anthropological methods proposed by different authors, whose reliability has proved to be most appropriate. Metrical morphology and non-metric variants in bones and teeth could give information about ancestry.

In palaeopathological analysis, bone surface and teeth are carefully observed looking for changes.

The more common diseases in bones are degenerative changes, infectious disease, trauma, congenital diseases (Figure 3) and stress indicators (hyperostosis and cribra orbitalia) (Ortner 2003). In teeth we can find cavities, calculus, periapical disease, and periodontitis. Wear isn’t considered with diseases but can lead to them. Another change that we can observe in teeth enamel is hypoplasia, a non-specific physiological stress that can give us information about nutritional or disease stress during infancy (Armelagos et al. 2009).

3.3. Population mobility and diet

After combining data from funerary archaeology and paleobiology, stable isotope analysis will be carried out to characterize the mobility and diet of a sample of individuals chosen from each cemetery.

All individuals chosen must be dated in order to assess contemporaneity, allowing data comparison.

Stable strontium isotopes (87Sr / 86Sr) are the most used tool in studies of mobility in ancient populations (Montgomery et al. 2005; Bentley 2006). They are measured in bones and teeth, functioning as markers of the geology of the areas where individuals grew up and where they died (Bentley 2006). Strontium is absorbed through food and incorporated into bones and teeth (Bentley 2006). Because Sr is predominantly deposited in skeletal tissues, the enamel and dentin of teeth are principally used for the analysis (Bentley 2006; Stallo et al. 2008). To define the values of the local Sr, local fauna remains and a sample of bone from each individual will be analyzed, which will allow an isotopic signature of the area (Bentley 2006). Bone remodels throughout life, absorbing the Sr levels of its environment. These values make it possible to compare the local Sr, the Sr of the human bone and the levels of Sr retained 147

PARTE II— Territorios en transición y creación de nuevos paisajes in the enamel of the teeth. If the Sr levels are different, these individuals will be considered ‘non-local’.

To Sr isotope analysis should be added oxygen stable isotopes (δ¹⁸O), offering information about water resources available at the place of birth (Bentley 2006). The samples should be molar teeth without visible pathologies (Bentley 2006).

In this project we also proposed to analyse diet through carbon stable isotopes (δ13C) and nitrogen (δ15N) of bone collagen, indicative of food protein or trophic level (Saragoça et al. 2016). The stable carbon isotopes (13C / 12C and δ13C) have traditionally been used to distinguish between a terrestrial or marine protein diet, based on the mechanisms of two photosynthetic groups of plants: C4 and C3 (Mays and Beavan 2012). Most of the plants in environments considered to be temperate belong to the C3 group, while the C4 group is composed mainly of grass considered tropical, such as millet, sugar cane and sorghum (Eckardt et al. 2015: 207). Nitrogen stable isotopes (δ15N) are used to distinguish between a diet rich in meat and a diet rich in plants and can also distinguish the consumption of marine or freshwater resources (Hedges and Reynard 2007).

To define the isotopic ratio of carbon and nitrogen, compact bone is preferably analysed. If possible, it is important to add a tooth to the bone sample because, while bone reflects the individual’s diet over the past 10 to 30 years, dentin preserves signs of diet during childhood. Important differences in the values of bone and dentin isotopes may be found that indicate a change of location (Hillson 2005; Eckardt et al. 2015). As for strontium stable isotope analysis, to determine the isotopic signature of potential food resources consumed by the population, it is also necessary to determine the values of local faunal remains (Saragoça et al. 2016).

Diet not only allows inferences about the type of food in a region at a given time, but it’s also a very important component in population mobility studies, since it can help to identify non-locals (Eckardt et al. 2015).

Finally, all results must be compared with other coeval realities, such as those identified as diocesan centres, for instance Braga, Viseu and Idanha-a-Velha, and with archaeological sites in rural areas, especially from the centre and north of the Iberian Peninsula.

4� Study relevance

The project presented here focuses on a geographical area of the Portuguese territory of the early medieval period with scarce bibliography. Generally, bone remains are not preserved given to the geology of the region (schist and granite). Thus, these cemeteries are unique, and their study can answer many archaeological questions.

The proposed multidisciplinary approach can answer several pertinent questions about these communities. How did they live? What did they eat? What social distinctions existed between community members? Were distinctions associated with age and/or sex? Did exogenous individuals live in the communities? Are we in the presence of different communities and this is expressed in their funerary rituals? Did individuals buried in diocesan churches live differently from those whose funeral practices were not integrated into the diocesan system? Did individuals buried with grave goods have a different lifestyle from the rest? These are some questions that we will try to answer, although many other questions will certainly emerge during the study. The final aim is to characterize the daily lives of these communities, combining paleobiological analysis and data from funerary anthropology, integrating them into the political and religious context of their time, and realizing a historical synthesis.

148

09— TERESO: Paleobiology of early medieval populations...

Bibliography

Alarcão, J. (2015): “Os limites das dioceses suevas de Bracara e de Portucale”. Portugalia, Nova Série, 36: pp. 35–48.

Almeida, F. (1962): “Arte visigótica em Portugal”. O Arqueólogo Português, Nova Série, 4: pp. 7–256.

André, C.; Fernández, A.; Carvalho, P. C.; Cipriano, M.; and Tereso, S. (2014): “Cerámicas romanas de la “Torre Velha” (Castro de Avelãs, Bragança). Primera sínteses”. In Morais, R.; Fernández, A. and Sousa, Mª J. (eds): Actas II Congreso Internacional SECAH, 2013 — As produções cerâmicas de imitaçao na Hispania. Vol.

1. Oporto: FLUP / SECAH, pp. 507–520

Arezes, A. (2014): Ocupação “germânica” na alta idade média em Portugal: As necrópoles dos séculos V a VIII.

Dissertação apresentada à Faculdade de Letras da Universidade do Porto, para obtenção do grau de Doutor em Arqueologia. PhD dissertation, Porto University.

Armelagos, G. J.; Goodman, A. H; Harper, K. N. and Blakey, M. L. (2009): “Enamel hypoplasia and early mortality: bioarchaeological support for the Barker hypothesis”. Evolutionary Anthropology, 18: pp.

261–271

Bentley, R. A. (2006): “Strontium Isotopes from the Earth to the Archaeological Skeleton: a Review”.

Journal of Archaeological Method and Theory, 13 (3): pp. 135–187.

David, P. (1947): Études historiques sur la Galice et le Portugal du VIe a XIIe siècles. Lisboa / Paris: Portugália Editora, Les Belles Lettres.

Díaz Martínez, P. (2011): El Reino Suevo (411–585). Madrid: Akal.

Eckardt, H.; Müldner, G. and Speed, G. (2015): “The Late Roman Field Army in Northern Britain?

Mobility, Material Culture and Multi-Isotope Analysis at Scorton (N Yorks.)”. Britannia, 46: pp. 191–223.

Ferreira, M. T. (2012): Para lá da morte: estudo tafonómico da decomposição cadavérica e da degradação óssea e implicações na estimativa do intervalo pós-morte. Tese de Doutoramento para a obtenção do grau de Doutor em Antropologia Forense, apresentada à Faculdade de Ciências e Tecnologia, Universidade de Coimbra.

PhD dissertation / Coimbra University.

Hedges, R. E. M. and Reynard, L. M. (2007): “Nitrogen isotopes and the trophic level of humans in archaeology”. Journal of Archaeological Science, 34: pp. 1240–1251.

Hillson. S. (2005): Teeth. Cambridge Manuals in Archaeology. 2ª Ed. Cambridge: Cambridge University Press.

Mays, S. and Beavan, N. (2012): “An investigation of diet in early Anglo-Saxon England using carbon and nitrogen stable isotope analysis of human bone collagen”. Journal of Archaeological Science, 39: pp.

867–874.

Montgomery, J.; Evans, J. A.; Powlesland, D. and Roberts, C.A. (2005): “Continuity or colonization in Anglo-Saxon England? Isotope evidence for mobility, subsistence practice, and status at West Heslerton”.

American Journal of Physical Anthropology, 126 (2): pp. 123–138.

149

PARTE II— Territorios en transición y creación de nuevos paisajes Ortner, D. (2003): Identification of Pathological Conditions in Human Skeletal Remains. San Diego (USA): Academic Press.

Palol Salellas, P. (1956): Esencia del arte hispánico de época visigoda: romanismo y germanismo. Settimanne di studio del Centro Italiano di Studi Sull’Alto Medievo. Spoleto: Arti Grafiche Panetto Petrelli.

Pereira, S.; Sastre Blanco, J.; Amorim, A.; Roiz, A.; Espí, I.; Liberato, M.; Cosme, S.; Rodrigues, Z.

and Paniagua Vara, E. (2015): “Espaços funerários no sítio de Crestelos do Baixo Império à Idade Média (Mogadouro, Portugal)”. In Quirós Castillo, J. A. and Castellanos S. (eds): Identidad y etnicidad en Hispania.

Propuestas teóricas y cultura material en los siglos V–VIII. Documentos de Arqueología Medieval 8. Bilbao: UPV, pp. 161–180.

Quirós Castillo, J.A.; Loza Urarte, M. and Nizo Lorenzo, J. (2013): “Identidades y ajuares en las necrópolis altomedievales. Estudios isotópicos del cementerio de San Martín de Dulantzi, Álava (siglos VI–X)”. Archivo Español de Arqueología, 86: pp. 215–232.

Santos, F.; Rosselló, M.; Santos, C.; Carvalho, L. and Rocha, F. (2016): “Aspetos da morte no vale do Sabor. O mobiliário funerário Tardo Antigo das inumações do Laranjal de Cilhades (Felgar, Torre de Moncorvo). Achegas à cronologia de uma necrópole de longa duração”. Arqueologia Medieval, 13: pp.

17–34.

Saragoça, P.; Maurer, A. F.; Šoberl, L.; Lopes, M. C.; Alfenim, R.; Leandro; I.; Umbelino, C.; Fernandes, T.; Valente, M. J.; Ribeiro, S.; Santos, J. F.; Janeiro, A. I. and Barrocas, C. D. (2016): “Stable isotope and multi-analytical investigation of Monte da Cegonha: A Late Antiquity population in southern Portugal”.

Journal of Archaeological Science, 9: pp. 728–742.

Stallo, J. R.; Shepartz, L. A.; Grimes, V. and Richards, M. P. (2008): “Strontium isotopes ratios and mobility reconstruction”. In Amore, M.G. (ed.): Necropolis of Apollonia. Tumulus 9. BAR International Series 2059. International Center for Albanian Archeology Monograph Series No. 2. Oxford: Archaeopress, pp.

78–84.

Tente, C. (2016): “O território”. In Paiva, J. P. (coord.): História da Diocese de Viseu, vol. I. Viseu: Diocese de Viseu: pp. 8–22.

Tereso, S.; Brito, A.; Umbelino, C.; Cipriano, M.; André, C. and Carvalho, P. (2015): “Arqueologia funerária alto medieval da Torre Velha (Castro de Avelãs, Bragança)”. In Quirós Castillo, J. A. and Castellanos S. (eds): Identidad y etnicidad en Hispania. Propuestas teóricas y cultura material en los siglos V–VIII.

Documentos de Arqueología Medieval, 8. Bilbao: UPV, pp. 145–160.

Vigil-Escalera Guirado, A. (2013): “Prácticas y ritos funerários”. In Quirós Castillo, J.A. (ed.): El poblamiento rural de época visigoda en Hispania. Arqueología del campesinado en el interior peninsular.

Documentos de Arqueología Medieval, 6. Bilbao: UPV, pp. 177–201.

150