I read something about a German from saxony fighting for the Swedes during the 30 years war and it implies that a lot of Germans were in the Swedish army is it true.
“"The history of Jürgen Schneeweiss prior to 1642 is unknown. Undoubtedly, he was among the many Germans recruited into the Swedish army during the Thirty Years War.” did the Germans of saxony join the Swedish army directly? I was under the impression that they would just join the electorate of saxony’s army and fight with the Swedes.
Absolutely, they did. Sweden used mercenaries extensively in the 30 Years War, with Germans being the largest nationality. (Scotsmen the second-largest) However the use of German mercenaries goes back well into the Middle Ages; the very word for mercenary in Swedish was/is legoknekt ('hired knight', where knekt is a borrowing of knecht from Middle Low German) The contacts there, as they had been with trade (read: the Hanseatic League) were mainly with north Germany though. So recruitment was primarily done from East Frisia, Lower Saxony, Pomerania/Stralsund and Prussia. Which naturally doesn't mean all soldiers came from there; some certainly came from Saxony. (e.g. the chronicle of Caspar Preiss documented his village being extorted by a mercenary in Swedish employ who was a Saxon with a Bavarian wife).