The Bṛhadāraṇyaka Upanishad is believed to be one of the older, “primary” (mukhya) Upanishads. 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 BCE. It is associated with the White Yajurveda. It figures as number 10 in the Muktika canon of 108 Upanishads and was notably commented upon by Adi Shankara.