Völsunga saga
According to Völsunga saga, Völsung was the son of King Rerir of Hunaland, in turn, a grandson of Odin. The king and the queen were struggling to have a child and so prayed to the gods for help. In response, Frigg gave an apple of fertility to Hljóð, the daughter of the jötunn Hrímnir, who travelled to the queen using her krákuhamr ("crow-shape"). Völsung's father the king died shortly after this, but the queen became pregnant for six years, until her health began to fail. She commanded that the child be delivered by caesarean section.
Völsung was born a well-grown child and was able to kiss his mother before she died. He was immediately proclaimed king of Hunaland, and when he had grown up he married Hljóð. Together they had ten sons and one daughter, including the twins Signy, their daughter, and Sigmund, the most courageous and beautiful of their sons.
Völsung built himself a great hall in the centre of which stood a large tree called the Barnstokkr. Siggeir, the King of the Geats, soon arrived and proposed to Signy. Both Völsung and his sons approved, but Signy was less enthusiastic. A great wedding was held in the hall, when suddenly a stranger appeared. He was a tall old man with only one eye and could not be anyone but Odin. He went to the tree, took his sword and stuck it deep into the trunk. Odin told everyone that the sword was meant for the man who could pull the sword from the tree. Then he vanished.
Everyone at the wedding tried to pull the sword but only Sigmund succeeded, and he did so effortlessly. Siggeir, his brother-in-law, offered thrice its weight in gold for the sword, but Sigmund scornfully said no. This greatly angered Siggeir, and he swore that one day the sword would be his and that he would avenge his humiliation upon the Völsung family. He returned home the next day, ending the wedding feast early. Before he left he invited the Völsungs to conclude the feast with him when the winter had passed.
Three months later Völsung and his sons sailed to Siggeir's land. They were met by Signy, who warned them that Siggeir intended to ambush them. They refused to turn back, whereupon Signy cried and implored them to go home. Soon they were attacked by Siggeir's army. Völsung fell and his ten sons were taken captive. His son Sigmund escapes and later avenges him by burning King Siggeir in his hall.