Trhisong Detsen ( Khri – srong lde – btsan ) (Chinese:赤松德赞) (born in 742, reigning from 755, died in 798 ) was the thirty-eighth ruler of Tibet and one of the 25 lobma ( disciples ) of Padmasambhava .
At his accession to the throne of the empire of the situation Songten Gampo ( Sron – btsan sGam – bit ) ( 617-649 ) had deteriorated with the loss , in 694, the territories of Xinjiang, in 703 with the loss of Nepal and with the increase of pressure in Kashmir Western Arab .
Trhisong Detsen favored the introduction and spread of Vajrayana Buddhism in Tibet as it was then prevalent in India in 779 declaring Buddhism the state religion. If in fact the arrival of Buddhism dates back to King Gampo Songten difffuso however this was only in court circles .
Following the difficulties encountered by Shantaraksita ( 750-802 ) in the spread of Buddhism in 786 Trhisong Detsen invited Padmasambhava in Tibet which gave her his own wife Yeshe Tsogyal ( Ye- shes ‘ Tsho – rgyal ) .
Padmasambhava made possible with magical practices implemented on the hill of Hepo Ri, the construction of the first Buddhist monastery in Tibet, Samye in the 787. By this time it was possible to begin the monastic life of the Tibetan people and provide a large translation project of the Buddhist literary corpus from Sanskrit into Tibetan .
It was at the monastery of Samye that , 792-794 , occurred the famous debate between the Chinese monks , supporters of Buddhism chan, and Kamalashila , a student of Shantaraksita , a supporter of Buddhism of Indian derivation . The first theorized the possibility of a sudden enlightenment , the latter stressed the importance of the path of the Bodhisattva and the guidance of a teacher ( Sanskrit guru , Tibetan lama ) to interpret the Indian texts . At the end of the Indian victory was not divorced from geopolitical reasons .
In fact, as early as 763 a Tibetan army of 200,000 men had entered China in the Tang Dynasty , taking advantage of the weakening caused by the rebellion of An Lushan , and had managed to conquer the capital Chang’an putting it on fire .
In 778 the war further internationalized the alliance with the king of Siam with Imobsun Trhisong Detsen and the joint attack on Sichuan.
Only in the 783 it came to a peace treaty that would establish the boundaries between China and Tibet. Not too curiously the Tibetan translation sounds like an agreement between equals, while the Chinese text makes it clear the subordinate position and tax of Tibet.
In the last decade of government Trhisong Detsen focused , in vain , in an attempt to wrest the region of the River Oxus , current Turkmenistan and Uzbekistan, the control of the Abbasid Caliphate of Harun al- Rashid ( 786-809 ) .
Trhisong Detsen was killed by an arrow in 798 ) by a suicide bomber linked to the circles of the nobility opposed to Buddhism and opponents of the policy of the sovereign.