From the time of the historical Buddha to the present day, an unbroken succession of great beings have achieved enlightenment and have dedicated themselves to teaching others the path that leads to awakening. Buddhism was brought from India to Tibet over several generations, starting with King Songtsen Gampo in the 6th century AD, and was finally established as the state religion under King Trisong Detsen in the 8th century AD. In Tibetan Buddhism there is a widespread tradition of recognizing the reincarnations of highly realized teachers. Such incarnations are known as tulkus. They take rebirth out of compassion, and to carry on the responsibilities of their previous incarnations. The Khyentses are such a lineage of reincarnate tulkus.