In 640 A.D., Songtsan Gambo, king of the Tubo kingdom, sent his trusted minister Kartongtsanyusung, also known as Lotongtsan in History of the Tang Dynasty, to Chang'an (today's Xi'an) to seek a bride from the Tang Dynasty court. Eventually, Tang Emperor Taizong agreed that Princess Wencheng marry the Tubo king.
Accompanied by Li Daozong, Minister of Rites of the Tang court and the Tubo minister, Princess Wencheng set out for the faraway Tubo. Arriving there in 641 A.D., the group was greeted at Heyuan by Songtsan Gambo. This showed the great importance that the Tubo kingdom was attached to the arrival of Princess Wencheng.
Songtsan Gambo's marriages with Princess Wencheng contributed much to Tubo's political, economic and cultural cooperation with Central Plains. Some agricultural technology and handicrafts, together with books on medicine and calendar calculation, were introduced into the Tubo Kingdom, largely advancing the local economic and cultural development.
In addition, Princess Wencheng was a Buddhist. She was said to have taken statues of Buddha and Buddhist monks with her. She also had the monasteries of Jokhang and Rampoche built, which were the earliest Buddhist temples in Tubo. The statue of 12-year-old Sakyamuni brought by Princess Wencheng was said to have been housed in the Rampoche.
Today, in Lhasa, capital of the Tibet Autonomous Region, the statue of Princess Wencheng is still enshrined and worshiped in the Potala Palace.
The Tang-Tubo Alliance Monument, which marks the meeting for this purpose between Tang and Tubo erected in 823 A.D., still stands in the square in front of the Jokhang Monastery.
The monument inscription reads in part, "The two sovereigns, uncle and nephew, having come to agreement that their territories be united as one, have signed this alliance of great peace to last for eternity! May God and humanity bear witness thereto so that it may be praised from generation to generation."