The tree of life is a fundamental archetype in many of the world's mythological, religious, and philosophical traditions. It is closely related to the concept of the sacred tree. The concept of the tree of life may have originated in Central Asia, and absorbed by other cultures, such as Scandinavian mythology and Altai shamanism. The tree of knowledge, connecting to heaven and the underworld, and the tree of life, connecting all forms of creation, are both forms of the world tree or cosmic tree, and are portrayed in various religions and philosophies as the same tree. Religion and mythology Various trees of life are recounted in folklore, culture and fiction, often relating to immortality or fertility. They had their origin in religious symbolism. According to professor Elvyra Usačiovaitė, a "typical" imagery preserved in ancient iconography is that of two symmetrical figures facing each other, with a tree standing in the middle. The two characters may variously represent rulers, gods, and even a deity and a human follower. Ancient Mesopotamia The Assyrian tree of life was represented by a series of nodes and criss-crossing lines. It was apparently an important religious symbol, often attended to in Assyrian palace reliefs by human or eagle-headed winged genies, or the King, and blessed or fertilized with bucket and cone. Assyriologists have not reached consensus as to the meaning of this symbol. The name "Tree of Life" has been attributed to it by modern scholarship; it is not used in the Assyrian sources. In fact, no textual evidence pertaining to the symbol is known to exist. The Epic of Gilgamesh is a similar quest for immortality. In Mesopotamian mythology, Etana searches for a 'plant of birth' to provide him with a son. This has a solid provenance of antiquity, being found in cylinder seals from Akkad (2390–2249 BCE). Urartu In ancient Urartu, the tree of life was a religious symbol and was drawn on walls of fortresses and carved on the armor of warriors. The branches of the tree were equally divided on the right and left sides of the stem, with each branch having one leaf, and one leaf on the apex of the tree. Servants stood on each side of the tree with one of their hands up as if they are taking care of the tree. Ancient Iran In the Avestan literature and Iranian mythology, there are several sacred vegetal icons related