may 15, 1648 - Peace of Westphalia ends the war
After more than 7 years of fighting, the war kind of seemed pointless. They were fighting for religion they more of fought for Politics. At the end, there was no definite winner, but the Protestants came up top. France stole some lands from the HRE which the Germans tried to get back in WW1. Switzerland became an independent country, Brandenburg(Early Germany) gained land, and the Spanish Netherlands became independent. This was a turning point in history because France was the new superpower in exchange from the HRE.
Added to timeline:
30 year war timeline