Vedic Sanskrit is the archaic form of Sanskrit in which the four Vedas, Hinduism's oldest scriptures, were composed, predating and grammatically distinct from Classical Sanskrit, the later standardized literary language codified by the grammarian Panini around the fifth century BCE; Vedic Sanskrit itself shows internal chronological layers, with the Rigveda's hymns representing its oldest stratum, composed roughly between 1500 and 1200 BCE, and the later Brahmana and Upanishad prose representing a somewhat later, more Classical-adjacent register.
Vedic Sanskrit belongs to the Indo-Aryan branch of the Indo-European family, and its close grammatical relationship to Avestan, the sacred language of Zoroastrianism, is one of historical linguistics' clearest demonstrations of a shared Indo-Iranian ancestor language, since the two share strikingly similar meter, vocabulary and even specific ritual and mythological terminology despite their geographic separation and doctrinal divergence. Vedic Sanskrit was preserved with extraordinary oral precision across millennia through specialized memorization and recitation techniques, developed specifically to guard against textual corruption before writing was used for the material.