This article was just published today so I thought that we can start a fresh thread about the Slavic Expansion.
Link:
https://www.nature.com/articles/s41586-025-09437-6
Abstract
The second half of the first millennium CE in Central and Eastern Europe was accompanied by fundamental cultural and political transformations. This period of change is commonly associated with the appearance of the Slavs, which is supported by textual evidence1,2 and coincides with the emergence of similar archaeological horizons3,4,5,6. However, so far there has been no consensus on whether this archaeological horizon spread by migration, Slavicisation or a combination of both. Genetic data remain sparse, especially owing to the widespread practice of cremation in the early phase of the Slavic settlement. Here we present genome-wide data from 555 ancient individuals, including 359 samples from Slavic contexts from as early as the seventh century CE. Our data demonstrate large-scale population movement from Eastern Europe during the sixth to eighth centuries, replacing more than 80% of the local gene pool in Eastern Germany, Poland and Croatia. Yet, we also show substantial regional heterogeneity as well as a lack of sex-biased admixture, indicating varying degrees of cultural assimilation of the autochthonous populations. Comparing archaeological and genetic evidence, we find that the change in ancestry in Eastern Germany coincided with a change in social organization, characterized by an intensification of inter- and intra-site genetic relatedness and patrilocality. On the European scale, it appears plausible that the changes in material culture and language between the sixth and eighth centuries were connected to these large-scale population movements.
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And another paper also published today:
https://genomebiology.biomedcentral....59-025-03700-9
Abstract
Background
The Slavs are a major ethnolinguistic group of Europe, yet the process that led to their formation remains disputed. As of the sixth century CE, people supposedly belonging to the Slavs populated the space between the Avar Khaganate in the Carpathian Basin, the Merovingian Frankish Empire to the West and the Balkan Peninsula to the South. Proposed theories to explain those events are, however, conceptually incompatible, as some invoke major population movements while others stress the continuity of local populations.
Results
We report high-quality genomic data of 18 individuals from two nearby burial sites in South Moravia that span from the fifth to the tenth century CE, during which the region became the core of the ninth century Slavic principality. In contrast to existing data, the individuals reported here can be directly connected to an Early-Slavic-associated culture and include the earliest known inhumation associated with any such culture.
Conclusions
The data indicates a strong genetic shift incompatible with local continuity between the fifth and seventh century, supporting the notion that the Slavic expansion in South Moravia was driven by population movement.

