The early Dravidian religion constituted a non-Vedic form of Hinduism in that they were either historically or are at present Āgamic. The Agamas are non-vedic in origin and have been dated either as post-vedic texts or as pre-vedic compositions. The Agamas are a collection of Tamil and Sanskrit scriptures chiefly constituting the methods of temple construction and creation of murti, worship means of deities, philosophical doctrines, meditative practices, attainment of sixfold desires and four kinds of yoga. The worship of tutelary deity, sacred flora and fauna in Hinduism is also recognized as a survival of the pre-Vedic Dravidian religion. Dravidian linguistic influence on early Vedic religion is evident, many of these features are already present in the oldest known Indo-Aryan language, the language of the Rigveda (c. 1500 BCE), which also includes over a dozen words borrowed from Dravidian. The linguistic evidence for Dravidian impact grows increasingly strong as we move from the Samhitas down through the later Vedic works and into the classical post-Vedic literature. This represents an early religious and cultural fusion or synthesis between ancient Dravidians and Indo-Aryans that went on to influence Indian civilization.
Ancient Tamil grammatical works Tolkappiyam, the ten anthologies Pattuppāṭṭu, the eight anthologies Eṭṭuttokai sheds light on early ancient Dravidian religion. Seyyon was glorified as, the red god seated on the blue peacock, who is ever young and resplendent, as the favored god of the Tamils. Sivan was also seen as the supreme God. Early iconography of Seyyon and Sivan and their association with native flora and fauna goes back to Indus Valley Civilization. The Sangam landscape was classified into five categories, thinais, based on the mood, the season and the land. Tolkappiyam, mentions that each of these thinai had an associated deity such Seyyon in Kurinji-the hills, Thirumaal in Mullai-the forests, and Kotravai in Marutham-the plains, and Wanji-ko in the Neithal-the coasts and the seas. Other gods mentioned were Mayyon and Vaali who were all assimilated into Hinduism over time. Dravidian influence on early Vedic religion is evident, many of these features are already present in the oldest known Indo-Aryan language, the language of the Rigveda (c. 1500 BCE), which also includes over a dozen words borrowed from Dravidian. The linguistic evidence for Dravidian impact grows increasingly strong as we move from the Samhitas down through the later Vedic works and into the classical post-Vedic literature. This represents an early religious and cultural fusion or synthesis between ancient Dravidians and Indo-Aryans, which became more evident over time with sacred iconography, traditions, philosophy, flora and fauna that went on to influence and shape Hinduism, Buddhism, Charvaka, Sramana and Jainism
Throughout Tamilakam, a king was considered to be divine by nature and possessed religious significance. The king was 'the representative of God on earth’ and lived in a “koyil”, which means the “residence of a god”. The Modern Tamil word for temple is koil (Tamil: கோயில்). Titual worship was also given to kings. Modern words for god like “kō” (Tamil: கோ “king”), “iṟai” (இறை “emperor”) and “āṇḍavar” (ஆண்டவன் “conqueror”) now primarily refer to gods. These elements were incorporated later into Hinduism like the legendary marriage of Shiva to Queen Mīnātchi who ruled Madurai or Wanji-ko, a god who later merged into Indra. Tolkappiyar refers to the Three Crowned Kings as the “Three Glorified by Heaven”, (Tamil: வாண்புகழ் மூவர், Vāṉpukaḻ Mūvar ?). In the Dravidian-speaking South, the concept of divine kingship led to the assumption of major roles by state and temple.
The cult of the mother goddess is treated as an indication of a society which venerated femininity. This mother goddess was conceived as a virgin, one who has given birth to all and one and was typically associated with Shaktism. The temples of the Sangam days, mainly of Madurai, seem to have had priestesses to the deity, which also appear predominantly a goddess. In the Sangam literature, there is an elaborate description of the rites performed by the Kurava priestess in the shrine Palamutircholai. Among the early Dravidians the practice of erecting memorial stones “Natukal’'had appeared, and it continued for quite a long time after the Sangam age, down to about 16th century. It was customary for people who sought victory in war to worship these hero stones to bless them with victory. Many Hindu sects such as Bhakti movement and Lingayatism originated in Tamil Nadu and Karnataka respectively. In addition to literary sources, folk festivals, village deities, shamanism, ritual theater and traditions, which are unique to the region, are also good indicators of what early Dravidian people believed/practiced.
The most popular deity is Murugan, he is known as the patron god of the Tamils and is also called Tamil Kadavul (Tamil God). In Tamil tradition, Murugan is the youngest son and Pillayar the oldest son of Sivan, it different from the North Indian tradition, which represents Murugan as the oldest son. The goddess Parvati is often depicted as having a green complexion in Tamil Hindu tradition, implying her association with nature . The worship of Amman, also called Mariamman, who is thought to have been derived from an ancient mother goddess is also very common. Kan̲n̲agi, the heroine of the Cilappatikār̲am, is worshipped as Pattin̲i by many Tamils, particularly in Sri Lanka. There are also many followers of Ayyavazhi in Tamil Nadu, mainly in the southern districts. In addition, there are many temples and devotees of Vishnu, Siva, Ganapathi, and the other Hindu deities.
In rural Tamil Nadu, many local deities, called aiyyan̲ārs, are believed to be the spirits of local heroes who protect the village from harm. Their worship often centres around nadukkal, stones erected in memory of heroes who died in battle. This form of worship is mentioned frequently in classical literature and appears to be the surviving remnants of an ancient Tamil tradition. The early Dravidian religion constituted a non-Vedic form of Hinduism in that they were either historically or are at present Āgamic. The Agamas are non-vedic in origin and have been dated either as post-Vedic texts or as pre-Vedic compositions. The Agamas are a collection of Tamil and later Sanskrit scriptures, chiefly constituting the methods of temple construction and creation of murti, idols that can have complex ways of representing deities, philosophical doctrines, meditative practices, attainment of sixfold desires and four kinds of yoga. A large portion of these deities continue to be worshipped as the Village deities of Tamil Nadu and Sri Lanka, and their subsequent influence in South-east Asia, examples of which include the Mariamman temples in Singapore and Vietnam. Worship of anthills, snakes and other forms of guardian deities and heroes are still worshiped in the Konkan coast, Maharashtra proper and a few other parts of India including North India which traces its origins to ancient Dravidian religion which has been influencing formation of mainstream Hinduism for thousands of years.
A hero stone, known as “Natukal” by Tamils and “Virgal” by Kannadigas, is a memorial commemorating the honorable death of a hero in battle. Erected between the 3rd century BC and the 18th century AD, hero stones are found all over India, most of them in southern India. They often carry inscriptions displaying a variety of adornments, including bas relief panels, frieze, and figures on carved stone. Usually they are in the form of a stone monument and may have an inscription at the bottom with a narrative of the battle. According to the historian Upinder Singh, the largest concentration of such memorial stones are found in the Indian state of Karnataka. About two thousand six hundred and fifty hero stones, the earliest dated to the 5th century have been discovered in Karnataka. The custom of erecting memorial stones dates back to the Iron Age (1000 BCE–600BCE) though a vast majority were erected between the 5th and 13th centuries AD.
Scholars regard Indian religions as a fusion or synthesis of various Indian cultures and traditions. Among its roots are the historical Vedic religion of Iron Age India, itself already the product of "a composite of the indo-Aryan and Harappan cultures and civilizations", but also the Sramana or renouncer traditions of northeast India, and mesolithic and neolithic cultures of India, such as the religions of the Indus Valley Civilisation, Dravidian traditions, and the local traditions and tribal religions.