I will reply to myself. The cold winter of 1658 froze the Great Belt, and allowed Swedish troups to march over the ice from Jutland to Zealand. This led to Swe

I will reply to myself. The cold winter of 1658 froze the Great Belt, and allowed Swedish troups to march over the ice from Jutland to Zealand. This led to Swedish victory over Denmark and the Treaty of Roskilde. This ceded significant territory to Sweden, much of which is Swedish to this day. https://en.wikipedia.org/wiki/March_Across_the_Belts https://en.wikipedia.org/wiki/March_Across_the_Belts