common Indo-Iranian religion remain visible, especially in the Soma cult and the fire worship, both of which are preserved in Zoroastrianism. Ethics in the Vedas are based on the concepts of Satya and Rta. Satya is the principle of integration rooted in the Absolute. Whereas, Ṛta is the expression of Satya, which regulates and coordinates the operation of the universe and everything within it. Conformity with Ṛta would enable progress whereas its violation would lead to punishment. Influence on Hinduism Around the beginning of the Common Era, the Vedic tradition formed one of the main constituents of the "Hindu synthesis". Vedic religion survived in the srayta ritual, whereas ascetic and devotional traditions like Yoga and Vedanta acknowledge the authority of the Vedas, but interpret the Vedic pantheon as a unitary view of the universe with 'God' (Brahman) seen as immanent and transcendent in the forms of Ishvara and Brahman. Later texts such as the Upanishads and epics, namely the Gita of Mahabharat, are essential parts of these later developments. Literature The reconstruction of the history of Vedic India is based on text-internal details, but can be correlated to relevant archaeological details. Linguistically, the Vedic texts could be classified in five chronological strata: Rigvedic text: The Rigveda is by far the most archaic of the Vedic texts preserved, and it retains many common Indo-Iranian elements, both in language and in content, that are not present in any other Vedic text. Its time span likely corresponds to the Late Harappan culture, Gandhara grave culture and Ochre Coloured Pottery culture. Mantra language texts: This period includes both the mantra and prose language of the Atharvaveda (Paippalada and Shaunmkiya), the Rigveda Khilani, the Samaveda Samhita (containing some 75 mantras not in the Rigveda), and the mantras of the Yajurveda. Many of these texts are largely derived from the Rigveda, but have undergone certain changes, both by linguistic change and by reinterpretation. Conspicuous changes include change of vishva "all" by sarva, and the spread of the kuru- verbal stem (for Rigvedic krno-). This is the time of the early Iron Age in north-western India, corresponding to the Black and Red Ware (BRW) and Painted Grey Ware (PGW) cultures, and the early Kuru Kingdom, dating from c. the 12th to 11th centuries BCE. Samhita prose texts: This period marks the beginning of the collection and codification of a Vedic canon. An important linguistic change is the