The thread is simple. How would you make lasting Piast (hereditary) Poland a powerhouse with equal strenghth as PLC had in OTL? I think, that there were three opportunities to have scenario like this. Firstly, we could have Boleslav I the Brave being more succesful and achieving his goal of unifying all Western Slavs under his rule and therefore creating the state containing all Obodrites, Velests, Lusatians, Czechs, Slovaks and OTL Poles in it's borders. It could be powerful, because Bohemia alone in Middle Ages was a powerful kingdom due to gold resources and we have Slovakia in this state also and Slovakia gave Hungary a lot of advantage (gold mines and copper mines) in Middle Ages. The expansion on the East could also happen in this scenario (I don't know if as advanced as in OTL) because "Polish" (it would be rather "Slavic" or "Slavonic") kings could take the role of TO OTL and start conquering Baltic tribes (but I don't know if it would be succesfull and if it would be - to how degree?). I think that this kingdom would be a mortal enemy of Hungary (the struggle for being greatest power in Eastern Europe, so no "Polish-Hungarian friendship") so we could see also "Polish" interventions in Red Ruthenia. The second possiblity is to have Boleslav II the Generous not deposed and crown maintained in his line. It would lead Poland to avoiding "The regional partitions" (IOTL they lasted from 1138 to 1318 and Poland never fully recovered, because it lost Silesia) and not waste the opportunities wasted by these period. The third option (but it would require a lot of luck) is have Casimir III have sons, these sons outliving Louis the Great and being old enough to marry one of his daughters, and therefore taking advantage from situation of Hungary. The Casimir's III lineage could also help Hussites in their struggle or marry Elizabeth of Luxembourg and gain her lands for themselves. Which possibility is the most interesting/most realistic one for You?