The medieval period in Europe was a time of unprecedented social, religious, political and economic change. In Poland, state formation, Christianization, transitions to market economies and urbanization occurred within a relatively restricted time period ca. AD 1000. Changes such as these influence food production and distribution, and may strongly impact human diet and health. Stable isotope analysis is a widely-used tool in anthropology that offers a sensitive and accurate measurement of diet that supplements and in some cases corrects previous historically- or archaeologically-based interpretations. I examine stable carbon and nitrogen isotopes from bone to assess changes in diet between the 2nd and 14th c. in North-Central Poland concurrent with sociopolitical upheavals.
Bone collagen and carbonate of 32 animals and 167 human skeletons are studied. The sites studied are from Rogowo (2nd c. AD), Kałdus (11th-13th c.) and Gruczno (12th- 14th c.)., along with four isolated skeletons from the Neolithic and the Iron Age. With this sample I investigate two primary predictions: 1) stable carbon and nitrogen isotope ratios increase significantly through time, reflecting an increase in consumption of marine fish concomitant with religious and economic change, and 2) stable isotope signatures from the medieval samples are more heterogeneous than those from pre- medieval samples and related to status (as estimated by grave goods) and sex. Change in
ii
the medieval sample can be studied with a chronological resolution of approximately 100-150 years between samples and an effort was made to ascertain a rate of diet change. Stable nitrogen isotope ratios of animals are higher than those usually reported for
Europe, revealing a different isotopic baseline for North-Central Poland that may result from land management strategies such as manuring and/or burning fields. The human samples studied here show evidence for consumption of millet, a uniquely Slavic cultigen in Europe that may be useful in studying Slavic migrations. My stable isotope data track millet consumption in Poland back to the Neolithic period (approximately 2,000 BC).
During the Roman Era, diet was terrestrial-based and included millet and some fish. At the onset of the medieval period, more fish were eaten and diet was highly variable. Contrary to expectations, throughout the medieval period diet became less isotopically varied. Diet at Kałdus was more varied than diet at Gruczno, which likely reflects the different economic functions of the two sites. There are no consistent relationships between burial style and diet, suggesting that differences in diet may not have been drawn on the lines of religion or status. Sex-based differences in stable isotope ratios are observed only in the Roman Era and the latest medieval period, Gruczno site 2, which most closely represents a “true” medieval village.
Rather than agreeing with broad trends expected on the basis of other European populations, diet changes in the study area depended more on local socioeconomic and political circumstances. Local conditions shaping diet in the study area include the shaky foothold of Christianity including pagan revolts after state-wide conversion, the influence of the Teutonic Order starting in the 13th c., and the waxing and waning of the study
iii
sites’ economic importance, independent of trends in Europe at large. These local particularities prevent assessment of a rate of change throughout the medieval period., although rate of diet change in small increments could be assessed at one site: Kałdus site 4 could be divided into five sub-phases, and over the course of 200 years the contribution of millet to diet decreased from 20% to 7%, an average of 2.6% per year.
The study samples were intended to isolate temporal diet change and control for regional and between-site variations. However, even in this very restricted geographic area, assessing temporal change in diet is not straightforward. Medieval settlements are socioeconomically diverse which complicates simple interpretations of diet change through time.