From Wikipedia on the Beaker Culture that started spreading rapidly across Europe about 5,000 years ago:
Given the unusual form and fabric of Beaker pottery, and its abrupt appearance in the archaeological record, along with a characteristic group of other artefacts, known as the Bell Beaker “package”, the explanation for the Beaker culture until the last decades of the 20th century was to interpret it as the migration of one group of people across Europe.
However, British and American archaeology since the 1960s had been sceptical about prehistoric migration in general, so the idea of “Bell Beaker Folk” lost ground, although recent genetic findings lend renewed support to the migratory hypothesis. A theory of cultural contact de-emphasizing population movement was presented by Colin Burgess and Stephen Shennan in the mid-1970s.
Under the “pots, not people” theory the Beaker culture is seen as a ‘package’ of knowledge (including religious beliefs and copper, bronze and gold working) and artefacts (including copper daggers, v-perforated buttons and stone wrist-guards) adopted and adapted by the indigenous peoples of Europe to varying degrees.
But today it turns out to have been People, Not Pots. Robert E. Howard proves once again to have had a better understanding of prehistoric Europe than cultural anthropologists.
Iñigo Olalde, et al
This article is a preprint and has not been peer-reviewed
Bell Beaker pottery spread across western and central Europe beginning around 2750 BCE before disappearing between 2200-1800 BCE. The mechanism of its expansion is a topic of long-standing debate, with support for both cultural diffusion and human migration. We present new genome-wide ancient DNA data from 170 Neolithic, Copper Age and Bronze Age Europeans, including 100 Beaker-associated individuals. … However, human migration did have an important role in the further dissemination of the Beaker Complex, which we document most clearly in Britain using data from 80 newly reported individuals dating to 3900-1200 BCE. British Neolithic farmers were genetically similar to contemporary populations in continental Europe and in particular to Neolithic Iberians, suggesting that a portion of the farmer ancestry in Britain came from the Mediterranean rather than the Danubian route of farming expansion.
Beginning with the Beaker period, and continuing through the Bronze Age, all British individuals harboured high proportions of Steppe ancestry and were genetically closely related to Beaker-associated individuals from the Lower Rhine area.We use these observations to show that the spread of the Beaker Complex to Britain was mediated by migration from the continent that replaced >90% of Britain’s Neolithic gene pool within a few hundred years, continuing the process that brought Steppe ancestry into central and northern Europe 400 years earlier.
See, the Russians are to blame.