Thangtong Gyalpo (Tibetan: ཐང་སྟོང་རྒྱལ་པོ་, Wylie: thang stong rgyal po) (1385 CE–1464 CE or 1361 CE–1485 CE), also known as Chakzampa, the "Iron Chain Maker" (Wylie: lcags zam pa), Tsöndrü Zangpo "Excellent Persistence" (Wylie: brtson 'grus bzang po), and the King of the Empty Plain. He was also known by a variation of this name, Madman of the Empty Valley. He was a great Buddhist adept, a Chöd master,yogi, physician, blacksmith, architect, and a pioneering civil engineer. He is considered a mind emanation of Padmasambhava and a reincarnation of Dolpopa Sherab Gyaltsen. He founded the Iron Chain lineage of the Shangpa Kagyu school of Tibetan Buddhism, and he recognized the first Samding Dorje Phagmo, Chökyi Drönma (1422–1455), the female incarnation lineage of Vajravarahi.
Thangtong Gyalpo is said to have built 58 iron chain suspension bridges around Tibet and Bhutan, several of which are still in use today. He also designed and built several large stupas of unusual design including the great Kumbum at Chung Riwoche, Tibet; established Gonchen Monastery in Derge; and is considered to be the father of a style of Tibetan opera called Lhamo. Associated with the Shangpa Kagyu, Nyingma and Sakya traditions of Tibetan Buddhism, and with the tradition of "mad yogis" known as nyönpa, Thang Tong Gyalpo is also known as a sorcerer character in the popular Tibetan story of Gesar. In addition, he is believed to be the most widely traveled person in Tibetan history.