When Odin arrived, he asked Mimir for a drink. The well’s guardian, knowing the value of such a draught, refused unless the seeker offered an eye in return. Odin – whether straightaway or after anguished deliberation, we can only wonder – gouged out one of his eyes and dropped it into the well. Having made the necessary sacrifice, Mimir dipped his horn into the well and offered the now-one-eyed god a drink.