Slavic history is absolutely wild with stuff like that. Eastern Europe has seen countless mass movements of people through it ranging from peaceful Romani migration from India to Operation Barbarossa torching, killing, and raping everything between Gdansk and Moscow.

Life in Eastern Europe has always been hard, and i really do admire the people that continue to live there after 3 thousand years of pillaging, plagues, famine, and genocide from all directions.i once had a history professor describe Eastern Europe as "the world's genetic dumping ground" which is pretty brutal, but fairly apt.