The traditional accounts of the early history of Tibetan Buddhism are far from unbiased. They do not portray accurately the history of Buddhism as it first moved into that country. The political/social context was far more complex than traditional accounts would lead one to believe.
Ch'an Buddhism was introduced into Tibet in three main currents. These are：from Kim Ho-shang's teachings, from Wu Chu's teachings and from Mo ho yen's teachings. The various forms of Ch'an gained wide popularity. So much so that the first Tibetan born abbot of the most important monistic center, bSam yas, was a Ch'an master. At the same time the rDzogs pa Chen po teachings from India were being introduced by Vimalamitra and Vairocana. Doctrinally there are considerable similarities between these two teachings. The teachings of Vimalamitra became very popular in the central district of Tibet. The teachings of Vairocana became popular in the areas of Tibet near the Chinese border.
The rNyingma master Rong Zom lived at the time of Atisa. Two generations before him the Ch'an teachings that survived after the suppression of Ch'an (in Tibet)，were unified with the rDzogs pa Chen po teachings of Vairocana. Rong Zom received the entire teachings of both Vimalamitra and Vairocana. He was the first person to do so. After the time of these two masters. Because the Ch'an teachings were already preserved in the system of Vairocana, with Rong Zom the whole of the rDzogs pa Chen po and Tibetan Ch'an were united.
This information is well documented in early rDzogs pa chen po texts and histories. Further references are to be found in The Blue Annals as well as material from Tun Huang.
