What if Lithuania gains both Pomerania and Mazovia instead of Bohemia having Silesia, what would be the effects of this on Poland in the long term..
Mazovia maybe, if luck is on Lithuania's side - their Grand Dukes had marriage ties to Mazovian dukes, so a few lucky marriages and early deaths could cut the case. Lithuania wasn't very interested in expansion West, though, unless it was reconquering Baltic lands.
Pomerania is practically impossible without a much different POD and situation. It was in the Holy Roman Empire, which Lithuanians did raid once, but never ever planned to take it's territory. And to take Pomerania with a contiguous territory, they'd have to annex the whole Teutonic Order, which was practically impossible for Lithuania without Polish help. And Poland would definitely take Pomerelia first, in that case...
It is possible to have this scenario, but with a wildly different POD. Somehow prevent the fall of Kievan Rus by the 1200s as well as the arrival of German monastic orders to Baltic territory, leading to a Lithuania that encompasses all Baltic lands but is unable to push east, so it decided to munch on Poland (which was, IIRC, divided at the time).
The problem is that this is such a different setting from the one we know in OTL that it's hard to make any clear guesses on what would happen.
This depends on which Prussia are we talking about.I think if the Lithuanians were able to take Prussia, they can take Pomerania..
Lithuania can conquer Baltic Prussia...the question is can they hold it.This depends on which Prussia are we talking about.
Baltic Prussia was very tough, they pushed back Polish invasions for two centuries, but I think Lithuania could integrate them within a reasonable timeframe. Ironically, in this timeline the Great Prussian Uprising would be against Lithuania...
Teutonic Prussia was practically impossible for Lithuania to take alone. They had superior castles, superior technology and reinforcements from the entirety of Christian Europe.
Lithuania couldnt hold Samogitia on its own and TK was besieging Vilnius. I doubt they could conquer PrussiaLithuania can conquer Baltic Prussia...the question is can they hold it.