What if one of the Dukes of Upper Silesia were able to unite Upper Silesia in 15th-17th Century and remain Polish speaking as well, I think they will try to ask PLC for help against the Habsburgs, how would this Polish or rather Silesian state in the HRE survive, would the PLC try to absorb it or would it survive as an independent state?
Would the Vasas or Jagellonians marry into them.
Would the Vasas or Jagellonians marry into them.