The Bronze Age was brought to Europe by the
Proto-Indo-Europeans, who migrated from the
North Caucasus and the
Pontic Steppe to the Balkans (from circa 6,000 years ago), then went up the Danube and invaded Central and Western Europe (from 4,500 years ago).
Italic-speakers, an Indo-European branch, are thought to have crossed the Alps and invaded the Italian peninsula around 3,200 years ago, establishing the Villanova culture and bringing with them primarily
R1b-U152 lineages and replacing or displacing a large part of the indigenous people. The Neolithic inhabitants of Italy sought refuge in the Apennine mountains and in Sardinia. Nowadays, the highest concentration of haplogroup G2a and J1 outside the Middle East are found in the Apennines, Calabria, Sicily and Sardinia.