Treaty of Copenhagen
1660 CE.
Shown on the map at 55.676°, 12.569°.
The Treaty of Copenhagen (Danish: Freden i København, Swedish: Freden i Köpenhamn) was signed on 27 May 1660, and marked the conclusion of the Second Northern War between the Swedish Empire and the alliance of Denmark–Norway and the Polish–Lithuanian Commonwealth. This treaty was a smaller follow-up treaty to that of the Treaty of Roskilde, which decisively delineated the mutually recognized boundaries of Denmark, Sweden, and Norway; boundaries which are almost exactly the same to this day.
Text from the Wikipedia article Treaty of Copenhagen (1660), licensed CC BY-SA 4.0.