The Upanishadic Period refers to a significant era in ancient Indian history marked by the composition of the Upanishads, philosophical texts that form the theoretical basis of Hinduism. This period, roughly spanning from 800 to 400 BCE, is characterized by a shift from ritualistic practices to introspective philosophy, focusing on concepts such as Brahman (the ultimate reality) and Atman (the self). The texts produced during this time have profoundly influenced spiritual thought and the development of Hindu philosophy.