Sometime after 10,000 BCE, as the ice sheet retreated from Northern Europe, a significant migration occurred from Anatolia and the near East. The size of the emigration that began at this time and continued in waves through the next 5 millennia is still debated, but there is clear evidence that at least some numbers, and perhaps more importantly, significant technology traveled across the Aegean and Black Sea regions during this period.
The evidence for this migratory wave partly comes from the incremental adoption of settled agriculture across the European peninsula. Scholars have argued that this could be brought about through colonization of the continent by those possessing the tools and organization needed for agriculture or that it could have simply been a case of cultural adaptation from frontier contacts westward. Few contend that this was a totally independent indigenous development.
In any case we see the development of the Neolithic Agricultural revolution beginning in the Greek peninsula around 9,000 BCE, reaching the Balkans by 7,000 BCE and Northwest Europe by 4,500 BCE. By 5,000-4,000 BCE there is evidence that original hunting-gathering societies had been replaced by domestic husbandry and agriculture (again, the question remains whether this was a demographic or a technological transition).
These new technologies allowed the creation of more elaborate arts and also fostered some trading across the European continents with clear cultural regional patterns.