The tale tells that Sigmund thought Sinfjotli over young to help him to his revenge, and will first of all harden him with manly deeds; so in summer-tide they fare wide through the woods and slay men for their wealth; Sigmund deems him to take much after the kin of the Volsungs, though he thinks that he is Siggeir's son, and deems him to have the evil heart of his father, with the might and daring of the Volsungs; withal he must needs think him in no wise a kinsome man, for full oft would he bring Sigmund's wrongs to his memory, and prick him on to slay King Siggeir.
Now on a time as they fare abroad in the wood for the getting of wealth, they find a certain house, and two men with great gold rings asleep therein: now these twain were spell-bound skin-changers,  and wolf-skins were hanging up over them in the house; and every tenth day might they come out of those skins; and they were kings' sons: so Sigmund and Sinfjofli do the wolf-skins on them, and then might they nowise come out of them, though forsooth the same nature went with them as heretofore; they howled as wolves howl but both knew the meaning of that howling; they lay out in the wild-wood, and each went his way; and a word they made betwixt them, that they should risk the onset of seven men, but no more, and that he who was first to be set on should howl in wolfish wise: "Let us not depart from this," says Sigmund, "for thou art young and over-bold, and men will deem the quarry good, when they take thee."
Now each goes his way, and when they were parted, Sigmund meets certain men, and gives forth a wolf's howl; and when Sinfjotli heard it, he went straightway thereto, and slew them all, and once more they parted. But ere Sinfjotli has fared long through the woods, eleven men meet him, and he wrought in such wise that he slew them all, and was awearied therewith, and crawls under an oak, and there takes his rest. Then came Sigmund thither, and said--
"Why didst thou not call on me?"
Sinfjotli said, "I was loth to call for thy help for the slaying of eleven men."
Then Sigmund rushed at him so hard that he staggered and fell, and Sigmund bit him in the throat. Now that day they might not come out of their wolf-skins: but Sigmund lays the other on his back, and bears him home to the house, and cursed the wolf-gears and gave them to the trolls. Now on a day he saw where two weasels went and how that one bit the other in the throat, and then ran straightway into the thicket, and took up a leaf and laid in on the wound, and thereon his fellow sprang up quite and clean whole; so Sigmund went out and saw a raven flying with a blade of that same herb to him; so he took it and drew it over Sinfjotli's hurt, and he straightway sprang up as whole as though he had never been hurt. There after they went home to their earth-house, and abode there till the time came for them to put off the wolf-shapes; then they burnt them up with fire, and prayed that no more hurt might come to any one from them; but in that uncouth guise they wrought many famous deeds in the kingdom and lordship of King Siggeir.
Now when Sinfjotli was come to man's estate, Sigmund deemed he had tried him fully, and or ever a long time has gone by he turns his mind to the avenging of his father; if so it may be brought about; so on s certain day the twain get them gone from their earth-house, and come to the abode of King Siggeir late in the evening, and go into the porch before the hall, wherein were tuns of ale, and there they lie hid: now the queen is ware of them, where they are, and is fain to meet them; and when they met they took counsel and were of one mind that Volsung should be revenged that same night.
Now Signy and the king had two children of tender age, who played with a golden toy on the floor, and bowled it along the pavement of the hall, running along with it; but therewith a golden ring from off it trundles away into the place where Sigmund and Sinfjotli lay, and off runs the little one to search for the same, and beholds withal where two men axe sitting, big and grimly to look on, with overhanging helms and bright white byrnies;  so he runs up the hall to his father, and tells him of the sight he has seen, and thereat the king misdoubts of some guile abiding him; but Signy heard their speech, and arose and took both the children, and went out into the porch to them and said--
"Lo ye! These younglings have bewrayed you; come now therefore and slay them!"
Sigmund says, "Never will I slay thy children for telling of where I lay hid."
But Sinfjotli made little enow of it, but drew his sword and slew them both, and cast them into the hall at King Siggeir's feet.
Then up stood the king and cried on his men to take those who had lain privily in the porch through the night. So they ran thither and would lay hands on them, but they stood on their defence well and manly, and long he remembered it who was the nighest to them; but in the end they were borne down by many men and taken, and bonds were set upon them, and they were cast into fetters wherein they sit night long.
Then the king ponders what longest and worst of deaths he shall mete out to them; and when morning came he let make a great barrow of stones and turf; and when it was done, let set a great flat stone midmost inside thereof, so that one edge was aloft, the other alow; and so great it was that it went from wall to wall, so that none might pass it.
Now he bids folk take Sigmund and Sinfjotli and set them in the barrow, on either side of the stone, for the worse for them he deemed it, that they might hear each the other's speech, and yet that neither might pass one to the other. But now, while they were covering in the barrow with the turf-slips, thither came Signy, bearing straw with her, and cast it down to Sinfjotli, and bade the thralls hide this thing from the king; they said yea thereto, and therewithal was the barrow closed in.
But when night fell, Sinfjotli said to Sigmund, "Belike we shall scarce need meat for a while, for here has the queen cast swine's flesh into the barrow, and wrapped it round about on the outer side with straw."
Therewith he handles the flesh and finds that therein was thrust Sigmund's sword; and he knew it by the hilts as mirk as it might be in the barrow, and tells Sigmund thereof, and of that were they both fain enow.
Now Sinfjotli drave the point of the sword up into the big stone, and drew it hard along, and the sword bit on the stone. With that Sigmund caught the sword by the point, and in this wise they sawed the stone between them, and let not or all the sawing was done that need be done, even as the song sings:
And Sigmund sawed,
Atwain with main
The stone was done."
Now are they both together loose in the barrow, and soon they cut both through stone and through iron, and bring themselves out thereof. Then they go home to the hall, whenas all men slept there, and bear wood to the hall, and lay fire therein; and withal the folk therein are waked by the smoke, and by the hall burning over their heads.
Then the king cries out, "Who kindled this fire, I burn withal?"
"Here am I," says Sigmund, "with Sinfjotli, my sister's son; and we are minded that thou shalt wot well that all the Volsungs are not yet dead."
Then he bade his sister come out, and take all good things at his hands, and great honour, and fair atonement in that wise, for all her griefs.
But she answered, "Take heed now, and consider, if I have kept King Siggeir in memory, and his slaying of Volsung the king! I let slay both my children, whom I deemed worthless for the revenging of our father, and I went into the wood to thee in a witch-wife's shape; and now behold, Sinfjotli is the son of thee and of me both! And therefore has he this so great hardihood and fierceness, in that he is the son both of Volsung's son and Volsung's daughter; and for this, and for naught else, have I so wrought, that Siggeir might get his bane at last; and all these things have I done that vengeance might fall on him, and that I too might not live long; and merrily now will I die with King Siggeir, though I was naught merry to wed him."
Therewith she kissed Sigmund her brother, and Sinfjotli, and went back again into the fire, and there she died with King Siggeir and all his good men.
But the two kinsmen gathered together folk and ships, and Sigmund went back to his father's land, and drave away thence the king, who had set himself down there in the room of king Volsung.
So Sigmund became a mighty King and far-famed, wise and high-minded: he had to wife one named Borghild, and two sons they had between them, one named Helgi and the other Hamund; and when Helgi was born, Norns came to him,  and spake over him, and said that he should be in time to come the most renowned of all kings. Even therewith was Sigmund come home from the wars, and so therewith he gives him the name of Helgi, and these matters as tokens thereof, Land of Rings, Sun-litten Hill and Sharp-shearing Sword, and withal prayed that he might grow of great fame, and like unto the kin of the Volsungs.
And so it was that he grew up high-minded, and well beloved, and above all other men in all prowess; and the story tells that he went to the wars when he was fifteen winters old. Helgi was lord and ruler over the army, but Sinfjotli was gotten to be his fellow herein; the twain bare sway thereover.
 "Skin-changers" were universally believed in once, in Iceland no less than elsewhere, as see Ari in several places of his history, especially the episode of Dufthach and Storwolf o' Whale. Men possessing the power of becoming wolves at intervals, in the present case compelled so to become, wer-wolves or "loupsgarou", find large place in medieval story, but were equally well-known in classic times. Belief in them still lingers in parts of Europe where wolves are to be found. Herodotus tells of the Neuri, who assumed once a year the shape of wolves; Pliny says that one of the family of Antaeus, chosen by lot annually, became a wolf, and so remained for nine years; Giraldus Cambrensis will have it that Irishmen may become wolves; and Nennius asserts point-blank that "the descendants of wolves are still in Ossory;" they retransform themselves into wolves when they bite. Apuleius, Petronius, and Lucian have similar stories. The Emperor Sigismund convoked a council of theologians in the fifteenth century who decided that wer-wolves did exist.
 Byrny (A.S. "byrne"), corslet, cuirass.
 "Norns came to him." Nornir are the fates of the northern mythology. They are three--"Urd", the past; "Verdandi", the present; and "Skuld", the future. They sit beside the fountain of Urd ("Urdarbrienur"), which is below one of the roots of "Yggdrasil", the world-tree, which tree their office it is to nourish by sprinkling it with the water of the fountain.