The 14th century was a tumultuous time in Great Britain: there were severely erratic weather patterns including an usually warm period, which led to a famine from 1315-1322, the Scottish were fighting for their independence in 1298-1328 and again from 1332-1357, and the Hundred Year war was being waged against France from 1337-1453. All of these factors led to migration, primarily into the city of London as it remained more stable than other rural areas. Using stable isotope analysis, archaeologists can track whether individuals were born in London or migrated in, which allows us to better interpret the latter population. Since cemeteries are often used over hundreds of years, it can be difficult to correlate specific problems or cultural processes to migration.
Kendall et al. (2013) use the cemetery of East Smithfield in London to examine migration patterns since it avoids this issue, due to it being in use only from 1348-1350. This means that any individuals with aberrant strontium and oxygen isotope ratios can be presumed to be migrants within a least a decade. This allows us to make more valid statements about the potential social processes that led to their migration. It was thought that the normal range of humans during the medieval period was 10 to 20 miles. However, the researchers propose that given the pressures of war, famine and disease, the normal mobility habits of people may have changed. The loss of their workforce and general decline in health may have caused increased movement into the city. Migration may have even been promoted to gain soldiers for the wars.
In the summer of 1348, the Black Plague hit Britain, and by the fall it had reached London. It spread quickly throughout the city leading to mass migration out and high mortality within. East Smithfield was purchased during this period as an emergency burial ground for plague victims. After two years it was closed to further burials due to the decline in plague deaths. There were both trenches and individual burials, all oriented east to west. A total of 195 individuals were recovered from the eastern side and 566 from the western. Preservation was fairly poor due to contamination, and it is thought that the cemetery may have held up to 2,400 individuals originally.
The goal of this study was to examine mobility during the mid-14th century into London through the use of stable isotope analysis. Specifically investigating strontium and oxygen ratios. Strontium isotopes are derived from the underlying geology, so it is passed onto humans through food sources. Oxygen isotopes are tied to geographical climate zones through water. Combined they allow for a fairly accurate estimation of the origin of an individual. 30 individuals were selected for the sample, specifically using the teeth as these preserve better and are static in ratios following growth.
The local range of isotope ratios was defined through comparison with other sites for what it considered the standard range of variation. London tends to have wide variation due to importing food rather than growing it locally. Further, all meat would be imported so comparison with animal bones, a traditional way of defining the local range, would not work in this case. Using the other sites as a baseline, the results showed that there were 8 outliers. Based on their ratios, 3 individuals appear to be migrants from the hinterlands, such as Norfolk. Each of these was a younger adult, so movement to the city may have been motivated by work. Famine is unlikely since it wasn’t as harsh in that area. One individual appears to have ratios concurrent with northern Scotland. 4 others had strontium levels consistent with London, but were outliers for oxygen, which places them on the Western coast likely. 2 of these are older individuals, and their presence may be due to famine in the region during that time.
The origins and reasons for migration are only possible interpretations. Without increased study of isotope ratios and comparison with other sites, it will be difficult to determine exact location. Further, we can only posit that the cultural and environmental processes occurring were related to their choice to migrate to London. However, this study does show that some individuals found buried at East Smithfield were either born far from London or traveled far at some point early in their life. Regardless of their reasons for this, it does show that we need to reassess our assumptions about medieval mobility.
Initially I had hoped this study would address mobility during the Middle Ages, and actually connect individuals to social processes that affect migration. While they were unable to specifically link migrants to events, they were able to address some lower levels questions. They show the assumptions regarding mobility must be re-examined, and add to knowledge about what the isotope ratio levels are for London populations. While they were unable to address the bigger cultural questions, they do create some interesting questions for the future and add to the body of current knowledge.
Kendall, E., Montgomery, J., Evans, J., Stantis, C., & Mueller, V. (2013). Mobility, mortality, and the middle ages: Identification of migrant individuals in a 14th century black death cemetery population American Journal of Physical Anthropology, 150 (2), 210-222 DOI: 10.1002/ajpa.22194