[1][2] Mistilteinn first belonged to Þráinn, who had been king in Valland before he retired in his burial mound with his wealth.
The Danish king Óláfr and his men, among whom Hrómundr Gripsson, learnt about that and found the barrow.
[3] Hrómundr used Mistilteinn during the battle between Óláfr and two Swedish kings both named Haldingr.
He killed Helgi inn frækni (the Valiant), who had slain his brothers.
He deeply felt this loss but soon recovered his sword, which was found in the stomach of a pike.