One of my family lines goes back to the late 1700s in Poland. The thing is, the family name is clearly German. In reading several Wikipedia articles, it's clear Poland was beaten up quite a bit during the Middle Ages including by their German neighbors.
I found this Wikipedia article that says Poland's immigrants were largely German settlers in the Middle Ages. How did these German people know that there was property for them in Poland? And migrating to the western part of Poland doesn't seem like too much of a stretch since it shared a border with Germany, but how did Germans get to the southeastern part of Poland? Through migration from the western part of Poland? Why would people be redistributed? Is there a record of who was assigned to go to Poland? Did they travel in large groups? What did they take with them? It's scary enough today, sometimes, to leave what you know for the unknown, but 500 years ago, it must've been just heart-wrenching to leave friends and family behind.
Are there any good books or websites to read about how people migrated to Poland in the Middle Ages?
The migration was a joint venture between the local land-holders (princes, monasteries, nobleman etc) and German partners (locators) who provided people and know-how about creating a viable new community.
For example, the location of Krakow in 1257 was based on a privilege granted by Prince Boleslaw V the Chaste to the locators Geidko Stilvoyt, Diethmar Volk and Jacob, Judge of Nysa (Neisse).
Location could be either a reorganization of existing settlement (like in Krakow) or a creation of a completely new one.
These agreements were supposed to be mutually beneficial for all sides involved: the prince was getting new subjects and (eventually) taxpayers and was putting previously empty or underdeveloped land to use; the common settlers were exempt from taxes for a number of years and privileges they might not have had in the own land; and the locators could negotiate some pretty sweet deals for themselves (in the case of Stivloyt, Volk and Jacob of Nysa they become joint hereditary mayors ("wójt") of Kraków, and the mayorship was extremely beneficial.