A legendary ṛṣi, closely associated with the White Yajur Veda, of which he is supposed to have been the first teacher. He appears frequently in its Brāhmaṇa, the Śatapatha, and its Upaniṣad, the Bṛhadāraṇyaka. In the latter, he is said to be the teacher of King Janaka of Videha, and is also described as becoming a parivrājaka or ‘wandering ascetic’. One of his wives is the theologically inquisitive Maitreyī. A Dharmaśāstra text, the Yājñavalkyasmṛti is also attributed to him.