The earliest evidence for prehistoric religion in India date back to the late Neolithic in the early Harappan period (5500–2600 BCE).[21][22] The beliefs and practices of the pre-classical era (1500–500 BCE) are called the "historical Vedic religion". Modern Hinduism grew out of the Vedas, the oldest of which is the Rigveda, dated to 1700–1100 BCE.[23] The Vedas center on worship of deities such as Indra, Varuna and Agni, and on the Soma ritual. Fire-sacrifices, called yajña were performed, and Vedic mantras chanted but no temples or icons were built.[24] The oldest Vedic traditions exhibit strong similarities to Zoroastrianism and other Indo-European religions.[25]

The major Sanskrit epics, Ramayana and Mahabharata, were compiled over a protracted period during the late centuries BCE and the early centuries CE[citation needed]. They contain mythological stories about the rulers and wars of ancient India, and are interspersed with religious and philosophical treatises. The later Puranas recount tales about devas and devis, their interactions with humans and their battles against demons.

Three major movements underpinned the naissance of a new epoch of Hindu thought: the advent and spread of Upanishadic, Jaina, and Buddhist philosophico-religious thought throughout the broader Indian landmass.[26] Mahavira (24th Tirthankar of Jains) and Buddha (founder of Buddhism) taught that to achieve moksha or nirvana, one did not have to accept the authority of the Vedas or the caste system. Buddha went a step further and claimed that the existence of a Self/soul or God was unnecessary.[27] Buddhism peaked during the reign of Asoka the Great of the Mauryan Empire, who unified the Indian subcontinent in the 3rd century BCE. After 200 CE several schools of thought were formally codified in Indian philosophy, including Samkhya, Yoga, Nyaya, Vaisheshika, Purva-Mimamsa and Vedanta.[28] Charvaka, the founder of an atheistic materialist school, came to the fore in North India in the sixth century BCE.[29] Between 400 BCE and 1000 CE Hinduism expanded at the expense of Buddhism.[30]

Sanskritic culture went into decline after the end of the Gupta period. The early medieval Puranas helped establish a religious mainstream among the pre-literate tribal societies undergoing acculturation. The tenets of Brahmanic Hinduism and of the Dharmashastras underwent a radical transformation at the hands of the Purana composers, resulting in the rise of a mainstream "Hinduism" that overshadowed all earlier traditions.[31]

Though Islam came to India in the early 7th century with the advent of Arab traders and the conquest of Sindh, it started to become a major religion during the later Muslim conquest in the Indian subcontinent.[29] During this period Buddhism declined rapidly and many Hindus converted to Islam. Numerous Muslim rulers such as Aurangzeb destroyed Hindu temples and persecuted non-Muslims; however some, such as Akbar, were more tolerant. Hinduism underwent profound changes, in large part due to the influence of the prominent teachers Ramanuja, Madhva, and Chaitanya.[29] Followers of the Bhakti movement moved away from the abstract concept of Brahman, which the philosopher Adi Shankara consolidated a few centuries before, with emotional, passionate devotion towards the more accessible Avatars, especially Krishna and Rama.[32]
The Swaminarayan Akshardham Temple in Delhi, according the Guinness World Records is the World’s Largest Comprehensive Hindu Temple[33]

Indology as an academic discipline of studying Indian culture from a European perspective was established in the 19th century, led by scholars such as Max Müller and John Woodroffe. They brought Vedic, Puranic and Tantric literature and philosophy to Europe and the United States. At the same time, societies such as the Brahmo Samaj and the Theosophical Society attempted to reconcile and fuse Abrahamic and Dharmic philosophies, endeavouring to institute societal reform. This period saw the emergence of movements which, while highly innovative, were rooted in indigenous tradition. They were based on the personalities and teachings of individuals, as with Ramakrishna and Ramana Maharshi. Prominent Hindu philosophers, including Aurobindo and Prabhupada (founder of ISKCON), translated, reformulated and presented Hinduism's foundational texts for contemporary audiences in new iterations, attracting followers and attention in India and abroad. Others such as Vivekananda, Paramahansa Yogananda, B.K.S. Iyengar and Swami Rama have also been instrumental in raising the profiles of Yoga and Vedanta in the West. Today modern movements, such as ISKCON and the Swaminarayan Faith, attract a large amount of followers across the world