The author of the bSam-gtan mig-sgron identifies himself as gNubs-ban and this is surely Nubchen Sangye Yeshe. He goes on to state that he had studied under various Indian and Nepali masters, and in particular with the Gilgit (bru-sha) translator Chetsunkye (lo-tswa-ba Che-btsun-skyes), who was largely responsible for translating the Anuyoga Tantras into Tibetan. These texts, under the designation rNal-'byor grub-pa'i lung, are much quoted in Nubchen's work. Some near contemporary critics, like Prince Zhiwa-od (Pho-brang Zhi-ba 'od, 10th cen. CE), accuse Nubchen of actually composing Nyingmapa Old Tantra texts himself and then passing them off as translations of indian originals. But the contents of the bSam-gtan mig-sgron show its author to be a scholar and a thinker aware of subtle philosophical distinctions. Later Nyingmapa tradition portrays Nubchen as a black-hat magician, a Tantrika (sngags-pa) indulging in the performance of black magic rites (drag-sngags, fierce mantras), and it is said that he was able to terrify and intimidate king Langdarma by means of his sorceries. However, there is no contradiction in his being both a scholar of philosophical bent and a magician; such was the case with several well-known figures of the Renaissance period in Europe.
According to the Nyingmapa tradition, Nubchen was born into the clan of Nub (gNubs) in the Drak Valley. At the young age of seven he became a master of the Tantras and received from Guru Padmasambhava the initiations for the sGrub-pa bka'-brgyad, the Sadhana Practices of the Eight Herukas. During the course of the initiation ceremony, when he tossed a flower into the Mandala of these Eight Herukas, it fell into the region of the Mandala associated with the residence of Yamantaka (gshin-rje gshed), the wrathful aspect of Manjushri, the Great Bodhisattva of Wisdom, who manifests dark indigo in color, having a horned buffalo head. After practicing the sadhana of Yamantaka for twenty-one days, he received a vision of the terrifying face of that meditation deity. Thus, Yamantaka became his yi-dam, or personal meditation deity that forms the basis of one's practice, and the glorious Bodhisattva Manjushri himself bestowed upon the boy a prodigious memory and a supreme intelligence. When he grew to adolescence, by means of his magical powers acquired through Yamantaka practice, he destroyed the compounds of thirty-seven warring hostile villages in Drak district and drove back their armed men with magically conjured fire. Indeed, through his meditation practice, he became the consummate master of the Fierce Mantras (drag-sngags), the black magic that destroys the enemies of the Dharma. In the cave of Drag-yang-dzang, his purpa, or three-bladed magic dagger, pierced the solid rock of the cliffside as if it were butter. It is said that Nubchen afterwards visited India, Nepal, and Gilgit, where he directly received teachings and secret instructions from Shrisimha, Vimalamitra, Shantigarbha, Dhanashila, Vasudhara of Nepal, and Chetsunke of Gilgit; and in Tibet he received esoteric teachings from Nyag Jnanakumara, Sogpo Palgyi Yeshe, and Zhang Gyalwe Yontan. Thus, all the lineages of transmission for Mahayoga, for Anuyoga, and for Dzogchen Semde converged in him.
When in the ninth century, King Langdarma and his hostile ministers set about to suppress the Indian Buddhist teachings and to close the Buddhist monasteries such as Samye, he summoned the Tantric master Nubchen Sangye Yeshe and his disciples into his presence, although all of them were not Buddhist monks but rather Tantrikas (sngags-pa). The arrogant king challenged Nubchen, inquiring, "And what power do you have?"
"Just observe the power I can manifest merely from the reciting of mantras!" Nubchen replied and raised his right hand in the threatening gesture of tarjini-mudra.
Instantly, in the sky above the Tantric sorcerer, the king saw nine giant scorpions appear, each the size of a wild yak. The king was terrified at this vision. So he promptly promised not to harm the white-robbed Buddhist Tantrikas and to refrain from disrobing and exiling them as he had done with the maroon-robbed Buddhist monks. Then Nubchen pointed again into the sky with a threatening gesture, and lightning flashed from heaven, shattering into pieces a nearby boulder.
Doubly terrified, the king vowed, "I will not in any way harm you or your white-robbed followers!" and he ordered that his prisoners be released. because of the mighty magical powers of this Tantrika Nubchen, the anti-Buddhist king could not destroy the esoteric teachings of the Mahayoga Tantras nor their white-robbed practitioners, the Ngakpas (sngags-pa, one who uses mantras). Subsequently, this Tantric Order of Nyingmapa Buddhists has flourished among the Tibetans until this day.
[Excerpted from The Golden Letters by John Myrdhin Reynolds, Snow Lion Publications 1996.]