“Like any earthly ruler, Odin handed out weapons to his chosen followers, and once they had received them, they were bound to give him loyal service till death and beyond it. Thus Sigmund the Volsung received a splendid sword, which the god himself brought into the hall and thrust into the great tree supporting the roof. The sword was regarded both as a family heirloom and a gift from Odin, and when Sigmund’s time came to die, Odin appeared on the battlefield and shattered the blade with his spear. The pieces of the broken sword were reforged for Sigmund’s son, Sigurd, who also found favour with Odin, and was given a wonderful horse bred from Odin’s own steed, Sleipnir.”
H. R. Ellis Davidson, Gods and Myths of Northern Europe, published in 1964.