The oldest layer of the tradition's textual inheritance, Rigveda, Yajurveda, Samaveda, and Atharvaveda, traditionally held as apaurusheya, without human author, heard rather than composed.
वैदिक काल · Vedic era
The Rigveda, the oldest of the four, is a collection of over a thousand hymns to the Vedic deities; the Yajurveda organizes ritual formulas for sacrifice; the Samaveda sets many Rigvedic verses to melody for chanting; and the Atharvaveda gathers spells, charms, and more everyday concerns, added latest of the four.
Each Veda carries layered strata, Samhitas (hymns), Brahmanas (ritual explanation), Aranyakas (forest texts), and Upanishads (philosophical treatises), meaning the same textual family holds both the tradition's earliest ritual poetry and, in its Upanishads, its most abstract philosophy. A fuller chapter on the Vedas and their preservation is still to come in this site's Dharma & Shastra chapter.