A religion, or more accurately, an loose coalition of belief systems that share continuity with each other and probably very little else. It is the native religious system of India together with a bunch of philosophy that ranges from materialism and atheism to polytheism to monotheism to monism. As it is a native religion, it has no well-defined beginning, founder, or any other organized source of authority, except maybe the Vedas which practically nobody knows or understands.