The Northern Seven Years' War (1563–1570) was a destructive conflict between Denmark-Norway and Sweden, with significant fighting taking place on Norwegian soil. The war, driven by long-standing territorial disputes and competition for dominance in the Baltic Sea, heavily impacted Norway, particularly its southern regions. As part of the Danish-Norwegian realm, Norway was drawn into the conflict, and its southern areas became battlegrounds for Swedish invasions and Danish-Norwegian defense efforts.
The war saw several key battles and raids in Norwegian territories, leading to widespread devastation in regions like Østfold and Bohuslän. Norwegian fortifications, such as the Akershus Fortress in Oslo, played important roles in the defense. The conflict strained Norway's already weakened economy and caused significant destruction to its infrastructure.
Although the war ended in a stalemate in 1570, with no major territorial changes, Norway suffered heavy losses in terms of property, population, and resources. The devastation left a lasting mark on the country, further weakening its economy and highlighting Norway’s vulnerable position as part of the Danish-Norwegian union.