The Brihadaranyaka Upanishad is one of the older, “primary” Upanishads commented upon by Shankara. It is contained within the Shatapatha Brahmana, and its status as an independent Upanishad may be considered a secondary extraction of a portion of the Brahmana text. This makes it one of the oldest (if not the oldest) texts of the Upanishad corpus, possibly dating to as early as the 9th century BC.
It is widely known for its philosophical statements, and is ascribed to Yajnavalkya. Its name is literally translated as "great-forest-book".
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