The Beguiling Of Gylfi

Gangleri asked: "How were things wrought, ere the races were and the tribes of men increased?"

Then said Hárr: "The streams called Ice-waves, those which were so long come from the fountain-heads that the yeasty venom upon them had hardened like the slag that runs out of the fire,--these then became ice; and when the ice halted and ceased to run, then it froze over above. But the drizzling rain that rose from the venom congealed to rime, and the rime increased, frost over frost, each over the other, even into Ginnungagap, the Yawning Void."

Then spake Jafnhárr: "Ginnungagap, which faced toward the northern quarter, became filled with heaviness, and masses of ice and rime, and from within, drizzling rain and gusts; but the southern part of the Yawning Void was lighted by those sparks and glowing masses which flew out of Múspellheim."

And Thridi said: "Just as cold arose out of Niflheim, and all terrible things, so also all that looked toward Múspellheim became hot and glowing; but Ginnungagap was as mild as windless air, and when the breath of heat met the rime, so that it melted and dripped, life was quickened from the yeast-drops, by the power of that which sent the heat, and became a man's form. And that man is named Ymir, but the Rime-Giants call him Aurgelimir."

From Gylfaginnin, The Prose Edda