enslaved gladiators63,64.
Across Europe, we see regional differences in the southeastern and 
southwestern expansions of Scandinavian-related ancestries. Early 
medieval groups from present-day Poland and Slovakia carry spe -
cific ancestry from one of the Scandinavian EIA groups—the one with 
individuals primarily from the northern parts of Scandinavia in the 
EIA—with no evidence of ancestry related to the other primary group 
in more southern Scandinavia (Fig. 2d). By contrast, in southern and 
western Europe, Scandinavian-related ancestry either derives from 
EIA southern Scandinavia—as in the cases of the probable Baiuvarii 
in Germany, Longobard-associated burials in Italy and early medieval 
burials in southern Britain—or cannot be resolved to a specific region 
in Scandinavia. If these expansions are indeed linked to language, this 
pattern is remarkably concordant with the main branches of Germanic 
languages, with the now-extinct eastern Germanic spoken by Goths in 
Ukraine on the one hand, and western Germanic languages such as Old 
English and Old High German recorded in the early medieval period 
on the other hand.
Influx into pre-Viking Age Scandinavia
In EIA Scandinavia (<500 ce), we find evidence for broad genetic homo-
geneity. Specifically, individuals from Denmark (100 ce–300 ce) were 
indistinguishable from contemporary people in the Scandinavian Pen-
insula (Fig. 2c). However, we observe a clear shift in genetic ancestry 
already in the eighth century ce (Late Iron Age/early Viking Age) on 
Zealand (present-day Denmark) for which a 100% EIA ancestry model 
is rejected (P = 1 × 10−17 using Twigstats; P = 7.5 × 10−4 without). This 
shift in ancestry persists among later Viking Age groups in Denmark, 
where all groups are modelled with varying proportions of ancestry 
related to Iron Age continental groups in central Europe (Figs.  3f  
and 4c). A non-parametric MDS of Viking Age individuals suggests 
that variation between individuals forms a cline spanning from the 
EIA Scandinavian Peninsula individuals to ancestry characteristic of 
central Europe (Fig. 4e). The observed shift in ancestry in Denmark 
cannot be confounded by potentially earlier unknown gene flow into 
Iron Age source groups in Austria, France and Germany, but such gene 
flow could affect the exact ancestry proportions.
These patterns are consistent with northward expansion of ancestry, 
potentially starting before the Viking Age, into the Jutland peninsula 
and Zealand island towards southern Sweden. The geographical ori-
gin of this ancestry is currently difficult to discern, as the available 
samples from Iron Age central Europe remain sparse. The timing 
of this expansion is constrained only by the samples available: this 
ancestry is not observed in individuals from the Copenhagen area of  
Denmark (around 100 ce–300 ce)6, an individual from the southern tip 
of Sweden (around 500 ce)16, individuals from the Sandby Borg mas-
sacre site on Öland in present-day Sweden (around 500 ce)7 and 31 indi-
viduals from the mid-eighth century Salme ship burials in present-day 
Estonia (Extended Data Fig. 9), who probably originated in central  
Sweden6. Therefore, this ancestry transformation most likely post- 
dated these individuals in each particular region and mostly occurred 
in the second half of the first millennium ce.
T o assess the full extent of the impact of this ancestry influx into 
Scandinavia, we next aimed to understand the ancestry of individu-
als in Scandinavia during the Viking Age. Previous studies have sug-
gested that there was a diversity of ancestries in Scandinavia during this 
period6,7,65, due to increased maritime mobility, but have not reported 
per-individual ancestry estimates based on preceding ancestry. We 
analysed each individual’s ancestry using a rotational qpAdm scheme 
(Fig. 4a, Extended Data Fig. 9 and Supplementary Table 4), which 
showed increased power in distinguishing models when restricted