The Sanskrit pre-Classical form is called Vedic Sanskrit . Rigveda, a Hindu scripture, dated from the middle to the late second millennium of BCE is the most attested Sanskrit text. If they still exist, no written documents from this early era can survive.
The Rigveda was developed by many writers from remote parts of ancient India. Such writers came from a number of generations, with mandala 2 to 7 being the oldest and mandala 1 and 10 being the youngest.
During the second half of the 2nd millennium BCE, according to Louis Renou — indologist, this means that the Sanskrit Vedic language had a "fixed language pattern" Besides Rigveda, Samaveda, Yajurveda and Atharvaveda, along with the inlaid and layered Vedic texts such as the Brahmanes, Aranyakas, and the early Upanishads are antique literature in Vedic Sanskrit that has survived until contemporary times.
The language spoken by the semi-nomadic Aryas was Vedic Sanskrit who settled temporarily in one place, kept cattle store, practised restricted agriculture and called gramma after a period of time by wagon trains. The Vedic Sanskrit or an Indo-European variant is known in a area which now belongs to Syria and Turkey and has been carved into the rock outside old India as evidenced by the "Mitanni Treaty" between the former Hittitis and Mitanni people.
Classical Sanskrit comes in the early upanishads of Hinduism as well as in recent Vedic literature, while archaic Vedic Sanskrit was incomprehensible to everyone but to ancient Indian sages.Pāṇini, along with Mahabhasya of Patanjali and Katyayana's remarks preceding Patanjali, are credited with formalization of the Sanskrit language. Panini composed Aṣṭādhyāyī.Pāṇini is conventionally taken to mark the beginning of classical Sanskrit, a detailed and scientific grammar theory.