Vishnupurana 3.4.p4

3.4.p4

There was but one Yaju Veda, which he divided into four parts—from which originated the sacrificial rite that is performed by the four orders of priests. In this, the Muni enjoined the Adhwaryu to recite the prayers of Yajuns; the Hotri to sing the hymn of (Rik-Veda); the Udgatri to sing the hymns of Shāma-Veda and the Brahman to utter the formulæ of the Atharva-Veda. He then compiled the Rig-Veda with the collection of these hymns (Richas); the Yajur-Veda with the prayers and directions named Yajush; and Shāma Veda, with those called Shāma; and with the Atharvas he laid down the function of the Brahman and the rules for the performance of all the ceremonies by kings.