We know it from Eric the traveller's S., Helge Thoreson's S., Herrand and Bose S., Herwon S., Thorstan Baearmagn S., and other Icelandic sources.

But the voyage to the Other Worlds are some of the most remarkable of the narratives Saxo has preserved for us.
"Hadding's Voyage Underground" .-- (a) A woman bearing in her lap angelica fresh and green, though it was deep winter, appears to the hero at supper, raising her head beside the brazier.

Hadding wishes to know where such plants grow.
(b) She takes him with her, under cover of her mantle, underground.
(c) They pierce a mist, get on a road worn by long use, pass nobly-clad men, and reach the sunny fields that bear the angelica:-- "Through griesly shadowes by a beaten path, Into a garden goodly garnished." -- F.Q.

ii.

7, 51.
(d) Next they cross, by a bridge, the "River of Blades", and see "two armies fighting", ghosts of slain soldiers.
(e) Last they came to a high wall, which surrounds the land of Life, for a cock the woman brought with her, whose neck she wrung and tossed over this wall, came to life and crowed merrily.
Here the story breaks off.