Mimir is said to have gained wisdom and knowledge by drinking from the Well of Wisdom. He is so wise that when the great tribes of Venir and Aesir gods are at war, the Venir tribe calls on him for counsel. But, incapable of translating his words of guidance, they behead him and send his head back to the Aesir tribe.
Odin, the Aesir chief, embalms Mimir’s head with herbs, casting a spell that empowers it to speak and share secrets. Thus Mimir guides Odin through the war until the two tribes of gods unify into one.