 The word "avatar" does not appear in the Vedic literature, however it appears in developed forms in post-Vedic literature, and as a noun particularly in the Puranic literature after the 6th century CE.Despite that, the concept of an avatar is compatible with the content of the Vedic literature like the Upanishads as it is symbolic imagery of the Saguna Brahman concept in the philosophy of Hinduism.The "Rigveda" describes Indra as endowed with a mysterious power of assuming any form at will.