John of Denmark

John of Denmark became king of the Kalmar Union, which united Denmark, Norway, and Sweden under a single monarch. The union was already weakened by internal conflicts. John's reign saw continued tensions with Swedish nobility who resisted central authority, leading to periodic rebellions.

John of Denmark led Danish forces against Swedish regent Sten Sture the Elder at Brunkeberg near Stockholm. The Danish army was defeated, and John failed to reclaim the Swedish throne. This battle solidified Swedish resistance to the Kalmar Union and delayed Danish control over Sweden.

John of Denmark signed the Treaty of Copenhagen with the Hanseatic League, ending a trade war. The treaty granted the Hanseatic League favorable trading rights in the Baltic, weakening Danish economic control. This agreement reflected John's inability to assert Danish dominance over the powerful league.