The Battle of Tønsberg was a battle between the Asgardians and the Frost Giants that was fought in what is now Tønsberg, Norway.
Taking place in 965 A.D., Laufey, the king of the Frost Giants, violated a peace agreement with Odin and attempted to conquer the Nine Realms, beginning the Asgard-Jotunheim War.
The war eventually reached Earth, where the Frost Giants invaded the small Viking village in what is now Tønsberg, Norway. Using the Casket of Ancient Winters, King Laufey murdered hundreds of human villagers, until the Asgardians assembled an army of their best warriors and drove the Frost Giants from Earth.
The war raged for months until the Frost Giants were driven back to Jotunheim.
The Asgardians invaded Jotunheim and Laufey surrendered.