Battle of Finnburg
According to the Finnesburg Fragment, the Danish prince Hnaef came with sixty followers to visit and spent the winter at the Finnburg.  Finnburg was the fort of his brother-in-law Finn, king of the Frisians. There a fight started between the Frisians and the Danes.  A battle took place that lasted for three days. The verses of the story that were found (which is thought to be a small part of the original work) do not explain why the fight started, nor do they give the outcome of the battle.