Farming or fishing?: A multi-sample approach to diet reconstruction through stable isotope analysis at (post-)Medieval Koudekerke, the Netherlands

In 2019, the skeletal remains of over fifty individuals were excavated in Koudekerke, Zeeland, the Netherlands. These individuals were buried at a former cemetery around the Michaëlskerk (Michael’s Church) which was in use for several centuries during the Late and post-Medieval period, in approximately four burial phases. In order to gain a better understanding of the lives of these individuals, this thesis attempts to reconstruct the diet of the Koudekerke population using stable carbon and nitrogen isotope analysis. Nine individuals have been selected for analysis of both dentine and bone collagen. Of all nine, two different molar samples and one bone sample have been collected. Because these tissues form during different life phases, the protein intake in childhood, adolescence and adulthood can be compared to gain insight into diet shifts over the life course of each individual. Additionally, overall diet between the four burial phases is also compared to investigate dietary...Show moreIn 2019, the skeletal remains of over fifty individuals were excavated in Koudekerke, Zeeland, the Netherlands. These individuals were buried at a former cemetery around the Michaëlskerk (Michael’s Church) which was in use for several centuries during the Late and post-Medieval period, in approximately four burial phases. In order to gain a better understanding of the lives of these individuals, this thesis attempts to reconstruct the diet of the Koudekerke population using stable carbon and nitrogen isotope analysis. Nine individuals have been selected for analysis of both dentine and bone collagen. Of all nine, two different molar samples and one bone sample have been collected. Because these tissues form during different life phases, the protein intake in childhood, adolescence and adulthood can be compared to gain insight into diet shifts over the life course of each individual. Additionally, overall diet between the four burial phases is also compared to investigate dietary changes within the population throughout the centuries. Previous research into contemporaneous diet in countries around the North Sea has shown that while diet predominantly remained based on terrestrial C3 sources, the contribution of marine fish increased over time with the widespread trade in predominantly cod products. In England, this process is theorised to have occurred quite quickly and suddenly starting around the year 1000 CE. This phenomenon is known as the ‘fish event horizon’. The results from Koudekerke are compared with those of other studies on a local (Domburg, Klaaskinderkerke and Vlissingen), regional (Slijpe, Koksijde, Alkmaar, Blokhuizen, Arnhem, Eindhoven and Zwolle) and international (Ipswich, Auldhame and Ribe) scale to better contextualise the findings. Comparison focuses on contemporaneous coastal sites around the North Sea, as well as a broader comparison within the Netherlands. This thesis shows that the protein intake at Koudekerke was at all times mostly derived from terrestrial C3 food, including plant sources such as cereals, vegetables and fruit, and herbivore and omnivore sources like dairy, mutton, eggs, pork and chicken. One individual from the first burial phase has significantly lower δ15N values than the rest of the group, which means this person relied more on plant protein and herbivore products than the others, who regularly consumed animal protein of a higher trophic level. Five individuals have higher stable nitrogen isotope ratios than would be expected from a purely terrestrial diet. These individuals therefore may regularly have eaten marine food. This is most convincingly the case for one of them, as this individual has both elevated δ15N and δ13C values. Freshwater fish consumption is also possible, as three individuals have at least one dentine sample that is high in 15N but low in 13C. Overall, the group exhibits an elevation in δ15N values over the four burial phases (with the highest values in phase 3 and the lowest in phase 1), which could indicate a rise in marine food consumption. However, comparison to Early Medieval Domburg does not reveal a sudden ‘fish event horizon’ as has been suggested for England. Alternative explanations for increasing δ15N are supplementing feed of terrestrial omnivores with seafood, intensification of manuring and/or an increase in freshwater fish consumption. There is no strong evidence for personal shifts in diet over individual lifetimes, but some tentative exceptions may exist. Comparison of Koudekerke to other contemporaneous sites shows that within the Netherlands, the Koudekerke population likely consumed more seafood than was average. It also shows a divide in isotope values between the two Belgian sites and the Dutch ones, as the Belgian sites have higher δ13C but lower δ15N values. Generally, an increase in δ15N likely linked to marine consumption over time can be seen at the sites used for comparison.Show less

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Farming or fishing? A multi-sample approach to diet reconstruction through stable isotope analysis at (post-)Medieval Koudekerke, the Netherlands