Mimir was the wisest of all beings in Norse myth — the keeper of the well of wisdom beneath the world-tree, the counsellor of the gods, whose severed head Odin preserved and consulted as an oracle. To gain even a single drink from Mimir's well, the All-Father gave up an eye; and so Mimir stands at the very source of divine wisdom in the Norse cosmos.
The Keeper of the Well
Mimir (Old Norse Mímir, “the rememberer”) was renowned above all for his wisdom and knowledge, the deepest and most learned of all beings. He was the guardian of Mimir's Well (Mímisbrunnr), a spring that lay among the roots of the world-tree Yggdrasil and whose waters held wisdom and understanding. Mimir drank from the well each day and was filled with all knowledge, and the well itself was a source of cosmic insight — the very fountain of wisdom welling up from beneath the structure of the worlds.
The Eye in the Well
Odin's endless hunger for wisdom brought him to Mimir's well, where he asked for a drink of its waters. Mimir demanded a price worthy of the gift, and Odin paid it without hesitation: he plucked out one of his own eyes and dropped it into the well. For that single eye, Odin won a drink of the waters of wisdom — and so the All-Father is forever one-eyed, his missing eye resting in Mimir's well as the price of his understanding. The image is one of the most profound in all of myth: that true wisdom must be paid for in sacrifice, that to truly see, one must give up an eye.
The Severed Head
Mimir's fate was bound up with the war between the Aesir and the Vanir. When the two divine races made peace by exchanging hostages, the Aesir sent Mimir (with the god Hœnir) to the Vanir. But the Vanir, feeling cheated when they realised Hœnir was useless without Mimir to advise him, beheaded Mimir and sent his head back to the Aesir. Odin, unwilling to lose the wisest of counsellors, took the severed head, embalmed it with herbs and sang charms over it so that it would not rot, and gave it the power of speech. Ever after, Odin kept Mimir's head and consulted it in times of need, drawing on its wisdom and its knowledge of hidden things — an oracle that whispered counsel to the All-Father from beyond death.
The Voice of Wisdom at the World's End
As Ragnarök approaches, it is told that Odin will ride to Mimir's well and take counsel with Mimir's head one last time, seeking wisdom for the final battle. Mimir endures as the very embodiment of wisdom in Norse myth — the keeper of the well, the price of Odin's eye, the severed head that speaks. He stands for the deepest truth of the Norse way of knowing: that wisdom dwells at the roots of things, beneath the world, in a well whose waters cost an eye to drink, and that even death cannot silence true counsel.
For one drink from his well, the king of the gods gave an eye — and even when the wisest of beings was beheaded, Odin would not let his counsel die, and keeps his whispering head to this day.