The teachings of Lord Buddha first began to flourish in Tibet during the seventh century A.D. Although the Buddhadharma first appeared in India, it gradually spread to many countries to the east and west, and eventually Tibet became a chief sanctuary for these blessed teachings. This occurred because many Tibetan lotsavas journeyed to India and translated a vast number of discourses by the Buddha and treatises by Indian pandits and siddhas from Sanskrit and other languages into Tibetan. Although these works were translated into numerous other languages, none of these translations were equal to those of the lotsavas. These lotsavas did not translate on the basis of their own whims or personal interpretations. Rather, they followed the Tibetan kings' command that translations be made by teams of qualified Indian pandits working together with skilled Tibetan lotsavas. These lotsavas were, in fact, emanations of buddhas and bodhisattvas. Their finished translations were presented to many Tibetan and Indian pandits for them to inspect, and they were not included in the Kangyur or Tangyur until they were found to be flawless.
Another reason for the superior quality of these translations is that the Tibetan written language was constructed on the basis of Sanskrit and Pali specifically in order to translate the Buddha's discourses and the later Indian treatises. The individual words and phrases of the original manuscripts were then directly translated into Tibetan without vagueness or uncertainty. Upon this solid foundation the entire body of the Buddha's Hinayana, Mahayana and Vajrayana discourses and the treatises of later Indian Buddhist pandits were translated into Tibetan.
This text is a concise account of the advent of Buddhism in general and the teachings of the Sakyapa tradition in particular on the basis of texts on this subject by great masters of the past.
~ excerpt from the preface