Massacre at Helgeandsholmen
1463 CE.
Shown on the map at 59.328°, 18.070°.
The Massacre at Helgeandsholmen, also called the Battle of Helgeandsholmen (Swedish: Slaget på Helgeansholmen) was a massacre by Danish troops under Ture Turesson Bielke against peasants from Uppland who had marched to Stockholm to protest the new tax and the imprisonment of Archbishop Jöns Bengtsson Oxenstierna. The massacre has been noted to be one of the lesser known massacres in Swedish history by Dick Harrison.
Text from the Wikipedia article Massacre at Helgeandsholmen, licensed CC BY-SA 4.0.