The Aitareya Upanishad is one of the older, "primary" Upanishads commented upon by Shankara. It is a Mukhya Upanishad, associated with the Rigveda. It figures as number 8 in the Muktika canon of 108 Upanishads. The Aitareya Upanishad is a short prose text, divided into three chapters, containing 33 verses. It comprises the fourth, fifth and sixth chapters of the second book of the older vedic text, Aitareya Aranyaka. The rishi of the Aitereya Aranyaka and the Aitereya Brahmana is Aitereya Mahidasa. In Chandogya Upanishad, Aitereya Mahidasa is said to have lived 116 years (Chhandogya 3.16.7).