Articles relating to Yggdrasil and its depictions. It is an immense and central sacred tree in Norse cosmology. Around it exists all else, including the Nine Worlds. Yggdrasil is attested in the Poetic Edda compiled in the 13th century from earlier traditional sources, and in the Prose Edda compiled in the 13th century by Snorri Sturluson. In both sources, Yggdrasil is an immense ash tree that is central to the cosmos and considered very holy.