In the medieval era, Judaism, Zoroastrianism, Christianity, and Islam arrived in India, and Sikhism emerged, all adding to India's diverse culture.
Much of northern India fell to the Delhi sultanate; southern India was united under the Vijayanagara Empire.
Buddhism, based on the teachings of Gautama Buddha attracted followers from all social classes excepting the middle class; chronicling the life of the Buddha was central to the beginnings of recorded history in India.
The Sangam literature of the Tamil language reveals that, between 200 BCE and 200 CE, the southern peninsula was being ruled by the Cheras, the Cholas, and the Pandyas, dynasties that traded extensively with the Roman Empire and with West and South-East Asia.
After the 10th century, Muslim Central Asian nomadic clans, using swift-horse cavalry and raising vast armies united by ethnicity and religion, repeatedly overran South Asia's north-western plains, leading eventually to the establishment of the Islamic Delhi Sultanate in 1206.