in a Christianity-influenced work by the skald Hallvarðr Háreksblesi: "There is not under the pole of the earth [Yggdrasil] an illustrious one closer to the lord of monks [God] than you." Theories Shamanic origins Hilda Ellis Davidson comments that the existence of nine worlds around Yggdrasil is mentioned more than once in Old Norse sources, but the identity of the worlds is never stated outright, though it can be deduced from various sources. Davidson comments that "no doubt the identity of the nine varied from time to time as the emphasis changed or new imagery arrived". Davidson says that it is unclear where the nine worlds are located in relation to the tree; they could either exist one above the other or perhaps be grouped around the tree, but there are references to worlds existing beneath the tree, while the gods are pictured as in the sky, a rainbow bridge (Bifröst) connecting the tree with other worlds. Davidson opines that "those who have tried to produce a convincing diagram of the Scandinavian cosmos from what we are told in the sources have only added to the confusion". Davidson notes parallels between Yggdrasil and shamanic lore in northern Eurasia: The conception of the tree rising through a number of worlds is found in northern Eurasia and forms part of the shamanic lore shared by many peoples of this region. This seems to be a very ancient conception, perhaps based on the Pole Star, the centre of the heavens, and the image of the central tree in Scandinavia may have been influenced by it.... Among Siberian shamans, a central tree may be used as a ladder to ascend the heavens. Davidson says that the notion of an eagle atop a tree and the world serpent coiled around the roots of the tree has parallels in other cosmologies from Asia. She goes on to say that Norse cosmology may have been influenced by these Asiatic cosmologies from a northern location. Davidson adds, on the other hand, that it is attested that the Germanic peoples worshiped their deities in open forest clearings and that a sky god was particularly connected with the oak tree, and therefore "a central tree was a natural symbol for them also". Mímameiðr, Hoddmímis holt, and Ragnarök Connections have been proposed between the wood Hoddmímis holt (Old Norse "Hoard-Mímir's" holt) and the tree Mímameiðr ("Mímir's tree"), generally thought to refer