Thang-stong rGyal-po (1361 - 1485) is known in the West primarily for erecting iron-chain suspension bridges. The Tibetan historians emphasize his role as religious teacher. The literature preserved by his lCags-zam sect is found in various sectarian collections.Thang-stong lived during the Phag-mo Gru-pa era. His lifestyle was that of the eccentric yogin who rejected societal mores. He studied several Buddhist traditions. During his early years he experienced numerous visions. In his later years he was involved in engineering projects. We also learn of his interaction with political leaders. He travelled to China, India, and Bhutan, and is believed to have sojourned in Uddiyana and Zangs-mdog dPal-ri. It is demonstrated that he lived for 124 years.As alternatives to the traditional teacher-to-disciple transmission (bka'-ma), Tibetan visionaries such as Thang-stong discovered hidden Treasure texts (gter-ma) and received sermons in revelatory trances (dag-snang). Indic precedents are found in some Mahayana scriptures, and in the spontaneous theophanies of the early centuries A.D. Visionary practises also trace to the early religions of Tibet. In its Buddhist contexts, the vision served as an authentication of innovative doctrine.The primary core texts which recorded revelations were modelled on the sutras and tantras. The Treasure Book and Vajrapada are examples of a "visionary document" literary genre. Due to their divine attribution, visionary documents were often anonymous. Exegetical and ritual texts were usually appended by later writers.Thang-stong's 'Gro-don mkha'-khyab-ma sadhana on Avalokitesvara is a simplified version of the older dMar-khrids. The 'Chi-med dpal-ster, based on his visions of Padmasambhava, is a "life-extending" meditation. The gSang-spyod sNyan-brgyud on gCod is traced to his vision of Ma-gcig Labs-sgron. Thang-stong's writings on the teachings of Niguma connect him to the Shangs-pas. The sPrin-gseb-ma on Panjara Mahakala, a Vajradhara guruyoga, and a Simhamukha meditation are also ascribed to him. His philosophical treatise concerning the "three doors to deliverance" may be extant.The Grub-thob thugs-tig, revealed to 'Jam-dbyangs mKhyen-brtse dBang-po, connects the thought of Thang-stong to rDzogs-chen and the Mayajalatantra.Thang-stong's contribution to Tibetan religion may be summarized as an attempt to simplify and popularize Vajrayana Buddhism. His concern for public accessibility is also illustrated by his unique involvement in engineering and building.
