No on knows when it exactly began. If you go by Hindu mythological stories, Hinduism is trillions of years old. If you go by Max Muller, the German philosopher, it is at least 8000 to 9000 years old. Since the recent archaeological discovery of the submerged coastal city at Poombuhar in Nagapattinam, Tamil Nadu, which is said to be older than the ancient Sumerians of Mesopotamia, and geological discovery of the (mythological) Saraswati river (which discredits the theory of the “Aryan invasion”), the Hindu culture seems to be that of the first modern human civilization.