History: Tibetan tradition traces the introduction of Buddhism back to King Srongtsan Gampo (ruled from around 629 to 649). He is said to have been converted to Buddhism by his wives, the Chinese princess Wencheng and the Nepalese princess Bhrikuti (historically disputed), to whom the founding of the Ramoche and Jokhang temples in Lhasa are ascribed. However, Buddhism was only elevated to the state religion in 791 by King Trisong Detsen (ruled from 755 to around 797), who enforced it against the resistance of local priests (Bon-po) and some noble families and around 779 with the help of the Indian teachers Padmasambhava and Shantarakshita founded the first Buddhist monastery in Tibet, Samye. It was there that the first translations of Buddhist texts into Tibetan were made in the Tibetan script, which was developed based on the Indian model. A dispute between followers of Indian Buddhism and those of Chinese Buddhism in Samye 792-94 is said to have been decided in favor of the Indian side.
The most important schools: After the persecution of Buddhists under King Langdarma († 842) and the subsequent fall of the dynasty, Buddhism experienced its “second expansion” in the 11th century, promoted by the western Tibetan kings Yeshe Ö and Jangchub Ö, who followed the monks to study India, including the later translator Rinchen Zangpo (* 958, † 1055), and brought the famous Bengali monk scholar Atisha (* 982, † 1054) to Tibet. His main student Domtön (* 1008 (?), † 1064) founded the more intellectually oriented Kadampa School in 1056(“Those bound by commandments”) with the Reting family monastery north of Lhasa. Her emphasis was on monastic discipline and the intensive study of Mahayana philosophy, especially the texts of the Prajnaparamita. Her following has always been small; it became part of the Gelugpa school at the end of the 14th / beginning of the 15th century.
According to percomputer.com, the spiritual ancestor of the Sakyapa school founded by the nobleman Könchog Gyalpo (* 1034, † 1102) in 1073 is his teacher Drogmi (* 992, † 1072). He had received tantric initiations in Hevajra Tantra in India and translated it into Tibetan. For the Sakyapa school, this tantra, which contains the exclusive invocation of the absolute (vajra), is the most important teaching text. The school produced eminent scholars and translators. The abbots of the ancestral monastery Sakya ruled over all of Tibet in the 13th and 14th centuries under Mongolian sovereignty as viceroys.
In 1150 Gampopa (* 1079, † 1153), a student of the famous hermit and yogi Milarepa, who in turn had been taught by the tantric master Marpa, founded the Kagyüpa school (“follower of authoritative tradition”). The Kagyüpa school traces its spiritual lineage through Naropa (* 1016, † 1100), the Indian Siddha and teacher Marpas, to Vajradhara, whom it worships as Adibuddha (“primordial Buddha”). The core of the Kagyüpa tradition or its most important meditation techniques, in addition to the Mahamudra teaching (Sanskrit “Great Seal”; the knowledge of “emptiness” [ Shunyata ] containing) the “Six Doctrines of Naropa “. Among Gampopa’s students and among the next generation of students, the school split into several branch schools, including the Karma Kagyu School (also known as the Karmapa School), which is still influential today. It was founded in 1185 by Düsum Khyenpa (* 1110, † 1193), the first Karmapa Lama, founded in central Tibet with Tshurpu as the parent monastery. Its head reincarnated for the first time in the 13th century in the form of a child as the third Karmapa Lama, a form of religious succession that was adopted by most other schools (tulku). From the middle of the 15th to the middle of the 17th century this was politically particularly influential. Another important branch is the Drukpa Kagyu School, which has been the dominant school in Bhutan since the 17th century.
In contrast to the schools mentioned so far, which have their origins in Buddhist India in the 11th century, the Nyingmapa school (“followers of the ancients [Tantras]”) traces its origins back to Padmasambhava, ie to the “first expansion of the teachings” in the 8th century. After the collapse of the royal power, their supporters in Eastern Tibet probably survived as “village tantrics”. The Nyingmapa School did not produce an organized hierarchy and only founded larger monasteries such as Dorjedrak, Mindoling, Kathog and others in the 17th century. Your allegedly from Padmasambhava and the “old” tantras introduced to his students were not recognized by the other schools and are therefore not included in the Tibetan canon. In the 15th century they were compiled in a separate »Compendium of Ancient Tantras« (Tibetan »Nyingmä Jübum«). Most of these texts are considered to be so-called Terma (Tibetan, “treasure”), which are said to have been hidden in the 8th century in order to move from the so-called Tertön (Tibetan, “revealer of treasures As has been proven in the meantime, some of these texts contain extensive ancient components. One of the best-known Terma texts is the Tibetan Book of the Dead (“Bardo Thödröl”). At the center of the tantric teachings of the Nyingmapa school, which are considered the revelation of Adibuddha Samantabhadra, is the meditation path Dzogchen (Tibetan, “great perfection”). Padmasambhava is venerated as the “second Buddha”.