The wisest god in the Norse pantheon is not Odin. No, he gets all his advice from Mimir, the severed head god of wisdom. With direct access to Yggdrasill, the World Tree, Mimir can draw on vast stores of knowledge. But how did he end up losing his head, or body?
The Norse people had not one, but two pantheons of gods vying for control. On one side you had the straightforward, battle centered Aesir with Odin and Thor. On the other side were the more cunning and magic oriented Vanir with Freyr and Freya.
When Freya visited the Aesir, they were taken by her use of seidr (a powerful magic). Enthralled, they soon threw aside kin loyalty and sought only selfish desires. The Aesir labeled Freya as “Gullveig” (“Gold-greed”) and tried to burn her to death three times, but she was reborn from the ashes.
War Between the Gods
This led to war between the Aesir and the Vanir. The Aesir fought by the established rules of combat, using weapons and their strength to vanish enemies. The Vanir fought with magic, a more subtle form of combat. Eventually, both sides realized that they were too evenly matched.
With the prospect of peace, it was customary for each side to send a tribute to the other, a god or goddess who would live among the foreign tribe of deities. Freya, Freyr and Njord were sent to live with the Aesir. Hoenir and Mimir took their place among the Vanir.
The Vanir Feel Cheated
Each time Hoenir sat in a meeting (called a Thing) with the Vanir, he would lean back and ask the more wise Mimir for advice. But one day, Hoenir went alone to the Thing. Each time he was asked to weigh in on a decision, he shrugged and said “Let others decide.”
The Vanir realized they had been cheated in the exchange of hostages. They’d sent their finest gods to the Aesir, but only received the dim-witted and indecisive Hoenir. In retaliation, they chopped off Mimir’s head and sent it back to Asgard. Apparently you need to pull your weight at a Vanir meeting.
Odin embalmed Mimi’s head with herbs to prevent rot. He also spoke charms over it, giving Mimir the power to speak again. Finally, Odin set Mimir at the foot of the Yggdrasil tree, next to a well. The well bore Mimir’s name, being known as the Mímisbrunnr.
Mimir the Keeper of Secrets
Mimir drank from the well and gained great knowledge and secrets. To accomplish this task, he used the drinking horn Gjallarhorn (which is the same one Heimdallr would blow to announce the coming of Ragnarök). How Mimir managed this drinking, given that he was only a head, the sources won’t divulge.
Now Odin sets himself up as the frontman for being the wisest in the land. He doles out all the witty saying to the other Aesir, with Mimir feeding him advice and secrets from the wings.
Odin spent countless hours wringing information from Mimir. You see, he valued Mimir’s knowledge as well as their intellectual discussions. But Ragnarök was coming soon and he needed to gather every scrap of information he could. Thus, Odin asked to drink from the well of Mímisbrunnr, himself.
This was a big ask. The well contained untapped knowledge of not only this world, but all the nine realms. As the keeper of Mímisbrunnr, Mimir wanted something in exchange. For the privilege of drinking, Odin sacrificed his right eye, which he tossed to the bottom of the well.
After this point, not much is mentioned about Mimir. Did he still give Odin council, or was he forgotten, now that Odin had drunk from the mystical waters of Mímisbrunnr. Given that Odin appears in comics and movies and Mimir is all but forgotten, I think we can guess the answer.