In the seventh century, as the Tibetan tribes coalesced into an organized kingdom, they became aware of sophisticated Buddhist civilizations in China and India. The “First Diffusion of the Dharma” into Tibet began when the Tibetan king Songtsen Gampo built a temple in Lhasa to house an image of the Buddha.
Under his successors, Tibetan Buddhism took on the complex institutional features of Indian Buddhism. The Indian saint Padmasambhava, or Guru Rinpoche, gave Tibetan Buddhism a Tantric character, and Shantarakshita introduced Tibetans to the intellectual traditions of the Indian monasteries.
With the arrival of Buddhism came the formation of a native Tibetan tradition known as Bon. Sometimes called the indigenous shamanism of Tibet, Bon is now so thoroughly infused by Buddhist influence that it seems little more than a variety of Tibetan Buddhism itself.