text: To develop an ancestry model for early medieval individuals (Supple- 
  mentary Table 1), we first need a broad characterization of the ancestry 
  of the earlier sources from the early Iron Age (EIA) and Roman periods. 
  We use hierarchical UPGMA clustering based on pairwise clade testing 
  between all individuals, and formally test the cladality of proposed 
  ancestry groups with qpWave5 (cladality in this sense means whether 
  they are consistent with being symmetrically related to all other tested 
  groups; Methods). This resulted in a set of model ancestry sources 
  that included Iron Age and Roman Britain (*n*= 11), the Iron Age of cen- 
  tral European regions of mostly Germany, Austria and France (*n*= 10), 
  Roman Portugal (*n*= 4), Roman Italy (*n*= 10), Iron Age Lithuania (*n*= 5), 
  the EIA Scandinavian Peninsula (Sweden and Norway,*n*= 10) and several 
  other more eastern groups dating to the Bronze Age and EIA (*n*= 25) 
  (Fig. 2a and Extended Data Fig. 1). We then use a rotational qpAdm 
  approach54 to narrow down the set of contributing sources from this 
  larger pool of putative sources. 