Prior to the introduction of Buddhism to Tibet, the majority of the Tibetan people practiced an animistic religion called Bon. Bon originated in Olmo Lungring, a region west of modern day Tibet; it then spread east to Zhang Zhung and finally, to Tibet where it took root. It is still practiced by a minority of Tibetans today as well as, by a significant percentage of Lepchas, the indigenous inhabitants of Sikkim.

Unfortunately, although Tibetan history stretches back thousands of years, writing was only brought to Tibet with Buddhism. In addition to this hindrance, due to persecution of Bon religion, Bon adopted many Buddhist practices (and vice versa). So while we have a good oral history of Bon, no one knows how accurate it is and what the original Bon religion was like. A brief history of Tibetan Buddhism