Yggdrasil: The World Tree of Norse Mythology
Explore Yggdrasil, the World Tree of Norse mythology: its three roots, its wells, the four stags, the squirrel Ratatoskr, the Norns, and its role in Ragnarok.
Yggdrasil is the immense ash tree at the center of the Norse cosmos. Its name, in its most common reading, means “Odin’s horse” — a kenning for the gallows on which the Allfather hung himself for nine nights to win the runes — though the etymology has been interpreted in several other ways. The Poetic Edda refers to Yggdrasil variously as “the great tree,” “the lofty ash,” and “Mímameiðr” (“Mímir’s tree”), and the Prose Edda of Snorri Sturluson gives the most complete account of its structure and the beings that inhabit it. Together, Yggdrasil, its three roots, its four stags, the squirrel Ratatoskr, the serpent Níðhöggr, and the three Norns form a single cosmological image in which the world is at once a place of being, a place of slow decay, and a place of constant renewal.
This page traces the structure of Yggdrasil as it appears in the Eddic and skaldic sources, with a focus on the wells at its three roots, the creatures that depend on it, and the role it plays in the Norse eschatology of Ragnarok.
The Name and the Sources
The name Yggdrasill is attested in the Poetic Edda (especially the Völuspá, Grímnismál, and Hávamál) and in the Prose Edda, where Snorri explains it as a kenning for the gallows of Odin (Ygg = Odin; drasill = horse, in the sense of “horse that one rides” or “horse that carries one away”). The kenning is, in this reading, a poetic image of the world tree as a vehicle or scaffold for the god’s self-sacrifice. Other Old Norse names for the tree include Askr Yggdrasils (“Yggdrasil’s ash”), Mímameiðr (“Mímir’s tree”), and Laðravíðr (“tree of misfortune” or “tree of hurt”), each pointing to a different aspect of the tree’s nature.
The principal source for Yggdrasil is the Grímnismál, a poem of the Poetic Edda in which the disguised Odin, held captive by King Geirröðr, recites a long cosmographic poem. Stanza 31 of the Grímnismál gives the three roots of the tree, and stanza 32 names the four stags. The Völuspá provides the image of the three Norns drawing water from the well, and the Hávamál describes Odin’s self-sacrifice on the tree. The Gylfaginning of Snorri’s Prose Edda pulls these and other sources into a single, integrated account.
The Three Roots
Yggdrasil has three roots, each reaching down into a different world. The Grímnismál says:
“Three roots stand on three ways of the ash Yggdrasil; one reaches the Æsir, another to the frost-jötnar, the third to the realm of Hel.”
The first root extends upward to Asgard, the citadel of the gods, and is associated with the Well of Urðr (sometimes identified with Mímir’s Well in the sources). The second root extends to the lands of the Jotnar (giants), the ancient enemies of the gods, and reaches the Hvergelmir spring, source of all cold waters. The third root reaches down into Helheim, the cold underworld ruled by the goddess Hel.
This tripartite structure is the basic skeleton of Norse cosmology. The tree is, in effect, a vertical axis of being, and the three roots are the three moral poles of the Norse universe: divine order, primal chaos, and death.
The Well of Urðr
The Well of Urðr (Old Norse Urðarbrunnr) sits at the base of the root that extends into Asgard. The Völuspá describes the Norns as drawing “the bright water” from this well to nourish Yggdrasil, and the Prose Edda elaborates that they also sprinkle the tree with mud from the well to keep its bark white and clean. The name Urðr is the Old Norse word for “fate” or “that which has become,” and from it the name of the first Norn, Urðr, derives. The well is therefore not merely a watering hole for the cosmic tree; it is the source of the substance of fate itself, the sacred liquid out of which the past, present, and future are continuously distilled.
In Snorri’s telling, the Well of Urðr is also the place where the gods hold their daily council. There is a tension in the sources between locating Mímir’s Well and the Well of Urðr in the same place and keeping them distinct. Modern scholarship tends to treat them as related but separable, with Mímir’s Well being more specifically the source of wisdom and the Well of Urðr being the source of cosmic order and the nourishment of time.
Mímir’s Well
Mímir’s Well is the well of wisdom, hidden deep beneath one of Yggdrasil’s roots. Snorri relates that Odin sacrificed one of his eyes for a draught from this well, and that the price — losing a piece of the divine sensorium — was the entry fee for the knowledge of all things past, present, and to come. Mímir, the ancient being who guards the well, is himself a figure of immense antiquity, and some scholars connect him to the same figure who appears in the Irish tradition as Mider and in the early Welsh tradition as Nudd or Lludd. The well’s waters confer on those who drink from them the gift of cosmic memory — the kind of knowledge that allows Odin to recite forgotten genealogies, to see all the runes, and to perceive the events of Ragnarok before they come to pass.
Hvergelmir
Hvergelmir (“bubbling cauldron”) is the third and most primordial of the waters beneath Yggdrasil. The Gylfaginning identifies it as the source of all the cold rivers of the world — the Élivágar — and as the dwelling of many serpents, including Göinn, Móinn, Grábakr, Ófótr, and Sváfnir, with Níðhöggr being their chief. The Völuspá describes Níðhöggr as gnawing at the root of the tree from this spring, and the imagery of Hvergelmir as a place of cold, biting, primal waters connects it to the land of the frost giants and to the deeper reaches of Norse cosmology — the place where the world is most vulnerable to dissolution.
The Four Stags
According to the Grímnismál (stanza 32), four stags — Dáinn, Dvalinn, Duneyrr, and Duraþrór — browse the highest shoots of Yggdrasil, and their constant eating of the new growth is one of the forces of slow destruction that constantly erode the world order. The stags’ names are sometimes interpreted as meaning “the dead one,” “the unconscious one,” “the dawn-deer,” and “the muddy antler,” each pointing to a different aspect of the cosmic decay. Some scholars have connected the four stags to the four winds of Norse tradition, and the four stags have been taken to be the same as the four dwarfs at the corners of the world (Nordri, Sudri, Austri, and Vestri) who hold up the sky.
The Squirrel Ratatoskr
The squirrel Ratatöskr runs up and down the trunk of Yggdrasil, carrying “slanderous words” between the unnamed eagle who perches in the tree’s crown and the serpent Níðhöggr who gnaws at its roots. The Grímnismál is the source for this image, and it is one of the most famous passages in Old Norse poetry. Whether the eagle is a stand-in for Odin (who is sometimes said to take eagle-shape), the great eagle of the Völuspá who catches the wind, or simply a wild bird of the upper air is a matter of debate; the meaning of Ratatoskr’s errands is more stable: he is the carrier of gossip, the messenger of malice, the squirrel who keeps the cosmic arguments stoked by running back and forth between the heights and the depths.
The figure of Ratatöskr is a remarkable piece of Old Norse mythopoetic invention. The image of a small, chattering squirrel, running up and down a cosmic tree with insults from the heights to the depths, is at once a comic figure and a profound one: the cosmos is held together, in part, by the malice of its smallest inhabitants. Ratatöskr is the gossip of the universe, the one who ensures that the eagle in the heights and the serpent in the depths are not at peace, and that the slow war between the divine and the chthonic never ends.
The Norns
The three Norns — Urðr, Verðandi, and Skuld — sit at the foot of Yggdrasil and tend the tree. The Völuspá describes them as drawing water from the Well of Urðr to nourish Yggdrasil, mixing it with the white clay of the well to keep the tree’s bark clean, and then setting up the laws of men, deciding the length of lives, and choosing the lucky among men. The Prose Edda adds that they are the “first to come into being” among the divine beings and that they determine the fates of gods and men.
The Norns’ names are the past, present, and future tenses of the Old Norse verb verða (“to become”): Urðr is “that which has become,” Verðandi is “that which is becoming,” and Skuld is “that which shall be.” This grammatical naming is one of the most famous examples of Old Norse mythopoetic word-play, and it grounds the Norns in the structure of language itself: the three tenses are the three Norns, and the fates they assign are the fates that unfold in time.
The Norns’ place at the foot of Yggdrasil — drawing water from the Well of Urðr, whitewashing the cosmic tree — situates them in a role analogous to that of the Fates in Greek mythology, but with one important difference. The Greek Moirai spin and cut; the Norse Norns tend and nourish. They do not so much determine fate as keep the world in a condition that allows fate to unfold; the structure of being itself is their care, and when the world ends at Ragnarok, the Norns too are said to fade.
The Serpent Níðhöggr
The serpent Níðhöggr (“the striker in malice” or “the malicious striker”) gnaws at the lowest root of Yggdrasil, the root that extends into the cold waters of Hvergelmir. The Völuspá describes him as chewing the corpses of the dishonored dead in the strand of corpses (Náströnd) along the river of Hel, and Snorri locates his home at Hvergelmir. At Ragnarok, Níðhöggr is said to take to the air, and the Völuspá describes him as a great flying creature whose wings cause the sea to surge.
The figure of Níðhöggr is one of the most enduring in Norse mythology. He is the gnawer at the root, the force of slow destruction that constantly erodes the cosmic order, and he is the dragon of the underworld who waits at the world’s end. In the renewed world of the Völuspá’s closing stanzas, Níðhöggr is described as flying out of the dark mountains, suggesting that he too survives Ragnarok and continues his work in the new world.
The Tree in the Riddle of the Skaldic Verse
The Norse skaldic poets, from the 9th century to the 13th, used Yggdrasil and its related imagery as a rich source of kennings — compressed metaphorical phrases that name a thing by a figurative description. The world tree is “the mighty ash,” “the lofty tree,” “the three-rooted tree,” “the evergreen tree,” and dozens of other formulations. The skalds also used the imagery of the wells, the stags, the squirrel, and the serpent to compose verse on themes that had no obvious connection to the cosmology: the shield-burg is “the Yggdrasil of the battle” (a kenning for the war-host), the sword is “the serpent of the blood” (a kenning for the blade), and the ship is “the boat of the wave-swan” (a kenning for a seafarer’s vessel).
The fact that the Yggdrasil imagery could be so freely used in skaldic verse suggests that the cosmology of the world tree was deeply embedded in the consciousness of the medieval Scandinavian poet, even when the verse itself was on a wholly different subject.
Yggdrasil at Ragnarok
At Ragnarok, Yggdrasil is described as shuddering and groaning, and the entire cosmos trembles. The Völuspá says:
“Yggdrasil shudders, the great tree, when Garmr howls; the bonds break, the wolf runs, and from the deep the dragon flies.”
The image of the tree as a living being that suffers in the catastrophe of the world’s end is one of the most powerful in Old Norse poetry. The tree has been trembling and groaning throughout the world-age — under the assaults of the four stags, the squirrel, and the serpent — and at the end it finally breaks. The Völuspá’s closing stanzas describe the world rising green and fair from the sea, and the great tree is implicitly present as the Hoddmímis holt (“the grove of Hoddmímir”), the shelter in which the two human beings, Líf and Lífþrasir, hide from the fire of Surt to repopulate the world.
The shaking of Yggdrasil at Ragnarok is one of the signs of the dísablót of doom. The runes of the Völuspá and Vafþrúðnismál describe several such signs — the wolf swallowing the sun, the breaking of the bridge Bifrost, the breaking of the fetters of Fenrir and Loki, the rising of the World Serpent from the sea — and the shaking of the cosmic tree is one of the most striking.
Yggdrasil and the Odinic Self-Sacrifice
The image of Yggdrasil as a place of self-sacrifice is one of the most profound in Norse mythology. In the Hávamál, Odin describes his own self-sacrifice on the tree:
“I know that I hung on the wind-tossed tree nine long nights, wounded by spear, given to Odin, myself to myself.”
The reference is to Odin’s hanging himself on Yggdrasil for nine nights to win the runes — the sacred knowledge of writing, magic, and the structure of the cosmos. The image is a powerful one: the Allfather, the chief of the gods, hangs himself on the cosmic tree, wounded by his own spear (perhaps Gungnir, perhaps a sacrificial spear), in a state of ecstatic self-offering. The nine nights echo the nine worlds of the cosmos, and the wound is both a death and a birth — Odin’s old self dies, and his new, rune-wise self is born.
The fact that the world tree is called “Odin’s horse” in the standard kenning suggests that this self-sacrifice is not a unique event but is constantly recurring in the structure of the cosmos. The tree is always being climbed, always being hung from, always being a vehicle for the divine. The Norse myth of the cosmic tree is, in this sense, a myth of constantly renewed self-offering at the center of being.
The Tree in the Landscape of Cult
The image of Yggdrasil was not only a literary and cosmological construct; it had its place in the actual cult life of the medieval North. The grove (lundr, vé) was a central element of Norse cult practice, and the great trees that stood at the center of these groves were understood to be the conduits of the divine. The Völuspá’s opening stanza, in which the völva asks to be heard “from the holy seat” and the sons of Heimdall “set the high seat in the holy place,” is sometimes read as a description of an actual cult site with a great tree at its center.
The Temple of Uppsala in Sweden, described by Adam of Bremen in the 11th century, was a great cult site in which a sacred tree was venerated alongside the statues of Thor, Odin, and Freyr. The Temple at Hofstaðir in Iceland, excavated in the 1990s, was a longhouse with a great central wooden column that may have been understood as a world-supporter and the cult analogue of Yggdrasil. The persistence of the sacred grove in the medieval North, even after the conversion, is well attested: the Mære in Trøndelag, the Grasgård in Sogn, and the great tree of Barnstaðahólmi in Iceland (felled in 1003 by a Christian priest) are some of the best-known examples.
The Cosmic Tree in Comparative Perspective
The image of a world-supporting tree is found in many Indo-European and world mythologies. The Norse Yggdrasil has been compared to the Irminsul of the continental Saxons (a sacred standing post or tree mentioned in the Vita Lebuini and destroyed by Charlemagne in 772), the world-tree of the Iranian tradition, the axis mundi of various cultures, and the Tree of Life in Jewish and Christian tradition. The comparativist project of the 19th and early 20th centuries (associated with Friedrich Max Müller, Adalbert Kuhn, and Jacob Grimm) tended to read Yggdrasil as a relic of an older Indo-European tree-cult; modern scholarship is more cautious, treating the image as a Norse-specific construction that may draw on common Indo-European motifs but cannot be reduced to them.
The persistence of the tree-on-a-hill image in the medieval Christian imagination (the Tree of Life in Eden, the Tree of the Cross on Calvary) may also have influenced the way the Yggdrasil image was transmitted in the 12th and 13th centuries, and the Eddaic description of the tree may have been shaped, in part, by the awareness of Christian counterparts.