Drinking deeply of Mimir’s fount, Odin gained the knowledge he coveted, and he never regretted the sacrifice he had made, but as further memorial of that day broke off a branch of the sacred tree Yggdrasil, which overshadowed the spring, and fashioned from it his beloved spear Gungnir.
“A dauntless god
Drew for drink to its gleam,
Where he left in endless
Payment the light of an eye.
From the world-ash
Ere Wotan went he broke a bough;
For a spear the staff
He split with strength from the stem.”
Dusk of the Gods, Wagner (Forman’s tr.).