640s
The Old Book of Tang records that when the king of 泥婆羅, Nipoluo ("Nepal"), the father of Licchavi king Naling Deva (or Narendradeva), died, an uncle, Yu.sna kug.ti, Vishnagupta) usurped the throne. "The Tibetans gave him refuge and reestablished him on his throne [in 641]; that is how he became subject to Tibet."
Sometime later, but still within the Zhenguan period (627–650 CE), the Tibetans sent an envoy to present day Nepal, where the king received him "joyfully", and, later, when a Tibetan mission was attacked in present-day India by then minister of emperor Harshavardhan who had usurped the throne after emperor Harshavardhan's death around 647 CE, the Licchavi king came to their aid. Songtsen Gampo married Princess Bhrikuti, the daughter of King Licchavi.
The Chinese Princess Wencheng, niece of the Emperor Taizong of Tang, left China in 640 to marry Songtsen Gampo, arriving the next year. Peace between China and Tibet prevailed for the remainder of Songtsen Gampo's reign.
Both wives are considered to have been incarnations of Tara (Standard Tibetan: Drolma), the Goddess of Compassion, the female aspect of Chenrezig, where "Dolma, or Drolma (Sanskrit means Tara). As Sarat Chaundra explains, the two wives of Emperor Songtsen Gampo are venerated under this name. The Chinese princess is called Dolkar, of 'the white Dolma,' and the Nepalese princess Doljang, or 'the green Dolma.' The latter is prayed to by women for fecundity."
The Jiu Tangshu adds that Songtsen Gampo thereupon built a city for the Chinese princess, and a palace for her within its walls. According to Chinese sources, "As the princess disliked their custom of painting their faces red, Songtsen Gampo ordered his people to put a stop to the practice, and it was no longer done. He also discarded his felt and skins, put on brocade and silk, and gradually copied Chinese civilization. He also sent the children of his chiefs and rich men to request admittance into the national school to be taught the classics, and invited learned scholars from China to compose his official reports to the emperor."
However, according to Tibetologist John Powers, such accounts of Tibet embracing Chinese culture through Wencheng are not corroborated by Tibetan histories.
Songtsen Gampo's sister Sadmarkar was sent to marry Lig-myi-rhya, the king of Zhangzhung. However, when the king refused to consummate the marriage, she then helped Songtsen Gampo to defeat Lig-myi-rhya and incorporate the Zhangzhung of Western Tibet into the Tibetan Empire in 645, thus gaining control of most, if not all, of the Tibetan plateau.
Following the visit by the famous Chinese pilgrim monk Xuanzang to the court of Harsha, the king ruling Magadha, Harsha sent a mission to China which, in turn, responded by sending an embassy consisting of Li Yibiao and Wang Xuance, who probably travelled through Tibet and whose journey is commemorated in inscriptions at Rajagrha - modern Rajgir – and Bodhgaya.
Wang Xuanze made a second journey in 648, but he was badly treated by Harsha's usurper, his minister Arjuna, and Harsha's mission plundered. This elicited a response from Tibetan and Nepalese (Licchavi) troops who, together, soundly defeated Arjuna's forces at the Battle of Chabuheluo.
In 649, the King of Xihai Jun was conferred upon Songtsen Gampo by Tang Gaozong, the emperor of the Tang dynasty.
According to the Tibetan Annals, Songtsen Gampo must have died in 649, and, in 650, the Tang emperor sent an envoy with a "letter of mourning and condolences". His tomb is in the Chongyas Valley near Yalung, 13 metres high and 130 metres long.
