Anund Uppsale or Anoundus, 'Anund of Uppsala', (Old Norse: Önundr Uppsali), a son of Erik Björnsson of the House of Munsö, ruled Sweden together with his brother Björn at Haugi, according to Hervarar saga.
[1] The Hervarar saga recounts that Anund and his brother Björn succeeded king Erik Refilsson, their cousin.
A certain Herjulf Horn-breaker was the standard-bearer of King Halfdan the Black of Vestfold in Norway, the father of Harald Fairhair.
[5] Sometime in the 840s, Anund thus invaded Sweden with a large Danish host of 21 longships and 11 of his own, unexpectedly approaching Birka.
The Danes felt tricked, since "every merchant owned more than they had been offered" and wanted to make a surprise attack on Birka in order to burn and plunder it.
According to the Vita, Hergeir made the townsfolk turn away from the pagan gods and make promises to Christ the Lord in order to be saved.
The outcome was that there was no possibility to carry out the plan with any success, so that an attempt on Birka would bring bad luck to the Danes.