Under the root *( of the Ash Yggdrasil ) that goes to the frost giants is the Well of Mimir.Wisdom and Intelligence are hidden there, and Mimir is the name of the well's owner. He is full of wisdom because he drinks of the well from the Gjallarhorn. All-father went there and asked for one drink from the well, but he did not get this until he gave one of his eyes as a pledge. As it says in The Sibyl's Prophesy : Odin, I know all,where you hid the eyein that famous Well of Mimir.Each morningMimir drinks meadfrom Val-Father's pledge.Do you know now or what ? ( The Sibyl's Prophesy. 28 ) The Prose Edda