I never thought of it before, but I sure Poland’s and Germany’s ancestry have a lot in common.
The best I figure is that there were two Scandinavian migrations to Germany:
1. Germanic people (around 650 BC.)
2. Vikings (mid-11th century.)
At Wikipedia it says on the Germanic people “A deteriorating climate in Scandinavia around 850 BCE to 760 BCE and a later and more rapid one around 650 BCE might have triggered migrations to the coast of Eastern Germany and further toward the Vistula.”
If do a web search “Viking villages in Germany” and look at images results, you will see some recreate Viking villages. Just last week I hear in the word new that there are currently on going attempts to have some of the sites declared “Word Heritage Sites”.