KU Leuven geneticists discover two separate population groups that coexisted in early medieval Flanders
The early medieval period in Flanders is a period that is not very well-known, because of the limited historical and archaeological sources. A unique discovery from the seventh century in Koksijde allowed KU Leuven geneticists to use DNA research to reveal the ancestry of the people who inhabited Flanders during this time. The genetic diversity in the thirty skeletons found in Koksijde was surprisingly high and their DNA profiles show that groups from two different ancestries coexisted at the time: people with a North Sea - Germanic ancestry, and people with a Northern Gaulish ancestry. The results of the study were published in the scientific magazine PNAS.
In 2016, an observant crane operator found bone material during construction works in Koksijde. Archaeologists discovered traces of a late Merovingian settlement and a burial ground from the second half of the seventh to mid eighth century. KU Leuven researchers analysed the DNA of thirty skeletons from this burial ground. ’In Flanders, the bodies of the deceased were cremated for a long time, and the Koksijde skeletons are one of the oldest skeletons after the fall of the Western Roman Empire we can study in terms of genetic material,’ says Maarten Larmuseau, professor in genetics, who coordinated the study in collaboration with Toomas Kivisild (both KU Leuven researchers). ’The bone materials found in 2016 contain a wealth of information. We used it to determine who lived here at that time and how people lived together in groups.’
After the fall of the Western Roman Empire in 476 AD, Merovingian kings reigned over an area that spans over present Belgium, Luxembourg, France, Germany and the Netherlands, over the course of three centuries. This period had an important impact on Western history in terms of administration, culture and religion. Less information is known about the ancestry and way of living of the population at large. DNA analysis of the bones found in Koksijde, dating from the Late Merovingian period (circa 675’750 AD), provides new insights in this context.
A fusion of two groups of different ancestries
The DNA profiles of the bones in Koksijde show a high level of diversity, indicating that this was a dynamic and mixed community. The researchers distinguished two groups of different ancestries that coexisted in Flanders during the Merovingian dynasty: a large group of individuals with a ’North Sea - Germanic’ ancestry, whose genes match with their contemporaries in Great Britain and the Netherlands; and a smaller group with ’Northern Gaulish’ ancestry, which lines up with people from France from the Late Iron Age. Larmuseau explains: ’In the larger North Sea - Germanic group, the individuals are mostly distant relatives. This is not the case in the smaller Northern Gaulish group, where individuals also showed more bone wear.’ ’An interesting observation is that these two groups had different dietary habits, linked to genetic differences in their ability to process foods like milk for instance,’ adds professor Kivisild.
Among the Koksijde skeletons, the researchers found a mother-daughter relationship, where the mother came from the Northern Gaulish group and the father was part of the North Sea - Germanic group. The researchers concluded that there was a fusion between the two groups.
Our research shows that the bones in Koksijde do not belong to a small close-knit family, as we initially thought, but rather a large community where people from two different ancestry groups lived together. Without the DNA analysis, we would never have guessed this.’
Professor Maarten Larmuseau
The study also shows genetic links to late medieval skeletons found in the neighbouring village Wulpen. This suggests that the genetic influences from the early medieval period had a lasting impact on the composition of the Flemish population. ’Even though the Merovingian period might not be in our collective memory, this period proves to be very important for Flanders’ DNA,’ concludes Larmuseau.
