WI: Bohemia manages to keep Lusatia?

So Spain convinced Saxony to intervene against Bohemia during the 30 Years' War, in exchange for control over Upper and Lower Lusatia.

What would be required for Saxony NOT to intervene? What would be the overall ramifications for the remainder of the 30 Years' War?

Moreover, can Bohemia continue to hang onto the territory, or is the annexation of Lusatia and/or Silesia by Saxony or Brandenburg inevitable?
 
Don't think it is impossible. If you managed to get Bohemia free of Hapsburg control a few decades earlier it might fair off better during the war.
 
Top