Odin sacrificed one of his eyes for wisdom from Mímir’s well. The well, called Mímisbrunnr, was beneath one of Yggdrasil’s roots and held wisdom and understanding beyond ordinary human knowledge.
In the Prose Edda, Odin offers his eye as a pledge so he can drink from the well. The sacrifice reflects a central feature of his character: he relentlessly seeks knowledge, even when gaining it requires permanent pain or loss. Odin is also associated with prophecy, runes, poetry, and secret wisdom.
The story is sometimes simplified into “Odin lost an eye,” but the myth describes a deliberate exchange: he gave up one eye in return for a drink from the well. Mímir is the guardian or master associated with the spring. In the Poetic Edda, the sacrificed eye is remembered as Odin’s wager, reinforcing that wisdom came at a real cost.
Mímir later remains connected with counsel and knowledge. After his death, his head is preserved and Odin consults it, making Mímir one of the most important wisdom figures in Norse myth.