It was a common custom, which had come down from the remotest times, formally and solemnly to form ties of friendship between men by swearing one another foster-brotherhood. This relation was of a most sacred and binding character; those who made the compact pledged themselves to be unselfish and true to each other for life, and to share the same dangers.
These four Vikings first cut three long slices of turf in a semi-circular shape, the ends of which were fastened into the ground, and the loops raised so high that those who were to swear foster-brotherhood could go under them. Under these loops, they placed a spear inlaid with mystic signs, of such a height that a man could reach with his hand the nail fastening the socket of the spear-point to the handle.
The warriors on both sides had assembled to witness the ceremony. It was a beautiful summer day; the sun shone brilliantly, nature was smiling, birds were singing in the groves, butterflies and bees were flitting from wild flower to wild flower; no one could ever dream of the fierce conflict of the preceding days.
In the midst of profound silence, Sigurd advanced towards Ivar and the three other Vikings, and said to them: “You are aware that from immemorial time, it has been the custom of valiant men, who make this agreement of foster-brotherhood between themselves, that the one that lives the longest should avenge the others, if they are slain with weapons or otherwise.”
“Yes,” answered Ivar, Hjalmar, and Sigmund.
Then they prepared themselves for the oath of foster-brotherhood, which was sacredly binding, although not taken on the temple ring as oaths generally were. Sigurd, Hjalmar, Sigmund, and Ivar then passed under the loop, and drew blood from the hollow of their hands, and let it run together into the mould which had been cut under the loop of the turf, and mixed together the earth and the blood; thereupon they all fell on their knees, and took oaths to ratify their agreement, and called upon Odin, Frey, Njord, and the other gods as witnesses; and then they all clasped hands, according to ancient custom, as a seal to their oaths.
The four foster-brothers agreed that they would never rob traders and Bondi or other men, except when they must make a raid on land for their men in case of need, in which case they were to pay full value for what they took. Never were they to rob women, though they should find them temptingly rich, nor should women be brought on board their ships against their will; and should a woman show that this had been done against her will, the man of the crew found guilty of such a crime against this law should lose his life for it, whether he were powerful or not.
It was also agreed that they should possess in common the booty they might get on Viking expeditions, and that whichever lived the longest should have a mound raised over the others after the battle or otherwise, and place therein as much property as seemed to him most befitting their rank.
And be it told now, that to their death they loved each other dearly, and never violated in the slightest manner the duties that were imposed upon them by their compact of foster-brotherhood.
The first thing the four foster-brothers concluded to do in concert, after consultation, was to visit Gudmund, Sigurd’s father, who was a powerful Hersir, and ruled over the large island, called to-day Oland, near the coast of the present Sweden, and to apprise him of their new relationship. They set sail, and after a short and pleasant voyage, their ships cast anchor in a bay where to-day the quiet little town of Borgholm stands. At that time Gudmund’s burg stood there, and near by are still seen many graves and mounds of that period.