The Indo-Aryans invaded northern India around 1500 BCE, bringing with them their Caucasian features, Sanskrit language, Hindu religion, and caste system. They transformed ancient Indian society and regarded the native Dravidians as inferior. Aryan society was tribal in nature and male-dominated, headed by chieftains. Hinduism and the Vedic texts they introduced, like the Upanishads and the epics Mahabharata and Ramayana, shaped Indian culture and promoted concepts like dharma, karma, and samsara.