Hinduism is the largest religion in South Asia with about 1.2 billion Hindus, forming just under two-thirds of South Asia's population. South Asia has the largest population of Hindus in the world, with about 99% of all global Hindus being from South Asia. Hinduism is the dominant religion in India and Nepal and is the second-largest religion in Bangladesh, Pakistan, Sri Lanka, and Bhutan.
Indo-Aryan migrations brought the Indo-Aryans to South Asia, where they compiled and composed the Vedic corpus during the Vedic period (ca. 1500-500 BCE) across present-day Northern India, Pakistan and Afghanistan. The subsequent period, between 800 BCE and 250 BCE, was "a turning point between the Vedic religion and Hindu religions", and a formative period for Hinduism, Jainism and Buddhism. The Epic and Early Puranic period, from c. 250 BCE and 500 CE, saw the onset of the Hindu synthesis, followed by the classical "Golden Age" of India (c. 350 - 650 CE), which coincides with the Gupta Empire.