The peoples of the North believe there are “Nine Worlds” (Niu Heimar) – nine realms that make up Creation. The Nine Worlds are linked by the connection of of the world-tree (usually conceived of as an ash tree) Yggdrasill (which means “Yggur’s Steed” – “Yggur” being a nickname of Odhinn, the reference being to the myth that Odhinn hung himself from the branches of Yggdrasill for nine nights in order to learn the secrets of the runes). Some tribes conceive of Yggdrasill as a sort of tree, others as a pillar (in Ethelland, sometimes it is called the pillar “Irminsul”). When a tree, it is sometimes called Askur Yggdrasill (the “Ash-tree Yggdrasill”).
One of the roots of Yggdrasill is near a sacred spring and the dwelling-place of the Nornir, the place where fate itself is woven for all those who dwell in the Nine Worlds, and prophecies are given with knowledge that transcends all Nine Worlds. Another root is located near the Well of Mimir, where flows another sacred spring of wisdom, where the head of the former god Mimir still whispers its oracles, the deep wisdom of the world. The god Odhinn has sacrificed much to have control of both sources of wisdom – the transcendent wisdom of the Nornir and the worldly wisdom of Mimir. Because Mimir‘s head is located under the root of Yggdrasill, it is sometimes called Mimameidhur ("Mimir’s Tree").
This great Tree of Life has many reflections throughout the universe, and is symbolized by sacred trees and pillars throughout the Nine Worlds. The Great Tree at Uppsalir is symbolic of Yggdrasill, as are lesser sacred trees (usually oaks or ash), and the sacred world-pillar symbol the Irminsul. There is also a mythical tree Laeradhur, “The Tree of Peace” (from lae – “calm”), which some believe to be identical with Yggdrasill. There are magical trees that are said to be cuttings from Laeradhur that induce peace and calm in those near them.