Swedish-Geatish wars

The Swedish-Geatish wars refer to semi-legendary 6th century battles between Swedes and Geats that are described in the Anglo-Saxon epic Beowulf. Little has survived of such battles in the Norse sagas, and later 11th century-13th century wars between Swedes and Geats, notably involving the Geatish clans House of Stenkil and House of Sverker, are referred to as Swedish civil wars.

The Anglo-Saxon epic relates that the Swedes did not keep the peace when the Geatish king Hreðel had died, because the Swedish king Ongenþeow's sons (i.e. Ohthere and Onela) had grown up and were eager to fight.

The Geats under their new king Hæþcyn captured the Swedish queen, but old king Ongenþeow saved her, at a hill fort called Hrefnesholt, although they lost her gold. Ongenþeow killed Hæþcyn, and besieged the Geats at Hrefnesholt. The Geats were, however, rescued by Hygelac, Hæþcyn's brother, who arrived the next day with reinforcements. Having lost the battle, but rescued his queen, Ongenþeow and his warriors returned home:

However, the war was not over. Hygelac, the new king of the Geats, attacked the Swedes:

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Wikipedia