Hinduism originated in India and has no single founder or centralized authority. It developed over time as a family of related beliefs influenced by Aryan invaders who entered India around 2000 BCE. The Aryans worshipped male gods and their sacred texts were the Vedas, which were orally transmitted. Later philosophical works called the Upanishads explored concepts like Brahman, Atman, Maya, Karma, Samsara and Moksha and emphasized liberation from the cycle of rebirth. Hindu society was traditionally organized by a caste system which determined one's social status and duties according to their occupation.