With great joy, we announce that in Genome Biology, one of the top three scientific journals dedicated to genetics (5-year IF 17.4), a paper entitled “Genetic history of East-Central Europe in the first millennium CE” has just been published (https://genomebiology.biomedcentral.com/articles/10.1186/s13059-023-03013-9). We believe that this work is a turning point in the over 200-year-long, heated debate surrounding the most fundamental issues concerning the origin of the Western Slavs, including society of the Piast state. The authors of this groundbreaking article are biologists, archaeologists, and historians forming an interdisciplinary research team led by prof. Marek Figlerowicz within the project “Dynasty and population of the Piast State in view of integrated historical, anthropological and genomic studies”, funded by the National Science Centre.

As it is widely known, the fall of the Western Roman Empire under the onslaught of barbarian tribes led to the emergence of entirely new political and ethnic structures in Europe. While historical events and processes underlying the transformation from antiquity to Christianity in the territories of the Empire are relatively well recognized, we still know little about the changes that occurred at the same time in areas not belonging to the newly formed Christian community. One of such events that still sparks numerous controversies is the appearance of the Slavs in Central Europe. To explain it, two opposing hypotheses were formulated many years ago. The first, allochthonous hypothesis, argues that the Slavs arrived in this region of Europe no earlier than the 6th century CE, while the second, autochthonous hypothesis, assumes that the Slavs inhabited the lands between the Oder and the Vistula long before the Migration Period, traditionally dated between 375 CE (invasion of Europe by the Huns) and 568 CE (conquest of Italy by the Longobards).

The data collected so far indicate that at the end of the late Neolithic period, 3700–1800 BCE, the genetic structures of the populations inhabiting Central Europe were stabilized and remained to a large extent unchanged until the end of the Bronze Age, 1800–700 BCE. During this period, three main genetic components constituted the genomes of the inhabitants of Central Europe. The first component was associated with Mesolithic western hunter-gatherers who arrived in Europe about 14 thousand years ago. The second component was linked to Neolithic Anatolian farmers who migrated to Europe 7-8 thousand years ago. The third component came from the steppe herders from the Caspian and Black Sea regions who spread across Europe 4-5 thousand years ago.

Questions related to the later shaping of the genetic history of Central and Eastern Europe have remained open for years, mainly due to the lack of appropriate material for archaeogenomic research as  cremation was a common funeral rite in this region from the Bronze Age until the Middle Ages. To solve this problem, we took advantage of the fact that in the early centuries CE, in the areas of contemporary Poland, inhumation (burial of corpses) became the dominant funeral practice among the population associated with the Wielbark culture. This population existed in the Vistula River basin between the 1st and 5th centuries CE. Most theories connect its formation with the migration of northern peoples commonly referred to as the Goths. Previous archaeological research indicates that until the 5th century CE, immigrants from the north lived alongside the local population, practicing cremation, which was associated with the previously established Przeworsk culture. The final stage of the coexistence of the Wielbark and Przeworsk cultures in the area of present-day Poland coincided with the Migration Period. After it ended, material cultures in this area became more homogeneous, and archaeologists commonly identified them with the Slavs, who continued to practice cremation until the baptism of the first Polish ruling dynasty (in 966 CE).

Considering the above facts, we decided to focus our multidirectional archaeogenomic research on two populations that inhabited the area of present-day Poland in the past. The first population consisted of representatives of the Wielbark culture. The second population was made up of representatives of the society of the Piast State. The research included 474 individuals buried in 27 cemeteries. For 197 of them, we succeeded to obtain whole-genome data.

The conducted analyses showed that the populations associated with the Wielbark culture were mainly composed of migrating men from the north and local women. Furthermore, we found that the genomes of individuals who were a mix of northern newcomers and the local population, contained practically all the genetic components present in the genomes of the population forming the society of the Piast State. This means that by the 5th century CE, the fundamental demographic processes shaping the genetic structure of the population inhabiting the area of present-day Poland in the 10th–12th centuries CE had already completed. In other words, the results of our research indicate that there was no additional migration after the 5th century CE that was necessary for the formation of the genetic structure of the inhabitants of the Piast State. Therefore, the presented results are consistent with the hypothesis assuming genetic continuity in the first millennium CE in the area of Central and Eastern Europe.