Tibet during the Jin, Sui and Tang Dynasties

During the Jin and Northern and Southern Dynasties, the Tibetan region was in a tripartite balance of power among the three major tribal alliances of Tubo, Zhangzhung, and Subi.

In the mid-4th century AD, Lhatotori Ningshe ascended the throne of Tibet. After three generations, the throne passed to Darniyase, the grandfather of Songtsen Gampo, who is well-known for marrying Princess Wencheng. Darniyase's son, and Songtsen Gampo's father, was Namri Songtsen. During the reigns of Darniyase and his son, Tibet's economy further developed. They used force to annex land, gradually expanding their influence into the Lhasa River basin. Namri Songtsen also personally rewarded his meritorious subjects with land and slaves. According to scholars, it was during this period that Tibet began to enter a slave society.

During the Sui Dynasty, the Eastern Women's Kingdom in Tibet maintained tributary relations with the Sui Dynasty. The Eastern Women's Kingdom was also known as Tangmao, and along with Yangtong and Fuguo, it was a tribal city-state in Tibet.

In 629 AD, the third year of the Zhenguan era of the Tang Dynasty, when Songtsen Gampo was 13 years old, his father, Namri Lunzan, was poisoned. Following this, his followers began to rebel. Simultaneously, the Yangtong tribe in the west invaded, and Subi also launched an attack on Tibet. Amidst this alternating internal and external turmoil, Songtsen Gampo ascended the throne and began to deal with the rebellions and attacks with a strong hand. After more than three years of warfare, he finally stabilized the situation and restored the unity of Tibet. In 632 AD, Songtsen Gampo led his army across the Yarlung Tsangpo River, moved the capital to Lhasa, and began to implement a series of annexation strategies.

Supi, located in northern Tibet, was a vast territory. Songtsen Gampo first conquered it, then destroyed the Yangtong tribe in western Tibet, and subsequently conquered the Dangxiang (Qiang people) and Tuyuhun (Xianbei people) in the east. With this, the Tibetan Plateau was completely unified, and Songtsen Gampo formally established the Tubo Dynasty, whose territory bordered Liangzhou and Songzhou of the Tang Dynasty to the east and India to the south.

After Songtsen Gampo established the unified Tibetan Dynasty, he married Princess Bhrikuti of Nepal and at the same time sought a marriage alliance with Princess Li Shimin of the Tang Dynasty. In 640 AD, he sent his minister Gar Tongtsen Yulsung with 5,000 taels of gold and hundreds of precious items to Chang'an to propose marriage to Emperor Taizong of Tang.

The following year, Emperor Taizong of Tang agreed to marry Princess Wencheng, a member of the imperial clan, to Songtsen Gampo. In 641 AD, when Songtsen Gampo was 25 years old, the Tang Dynasty dispatched Li Daozong, the Minister of Rites and Prince of Jiangxia, to escort Princess Wencheng to Tibet. Songtsen Gampo held a grand welcoming ceremony and built a city and palace for Princess Wencheng on Mount Maburri in Lhasa. From then on...

Songtsen Gampo introduced advanced production technologies such as brewing, milling, papermaking, and ink making from the Tang Dynasty. He also sent noble sons to Chang'an to study and invited Han Chinese scholars to lecture in Tibet. After Emperor Gaozong of Tang ascended the throne, he conferred upon Songtsen Gampo the titles of Imperial Son-in-Law and Prince of Xihai, and later Prince Bin.

Both of Songtsen Gampo's wives were Buddhists, and they brought Buddhist statues and scriptures with them when they entered Tibet. Influenced by them, Songtsen Gampo also began to embrace Buddhism and built the Jokhang and Ramoche temples in Tibet for them. In 650 AD, Songtsen Gampo died in Lhasa at the age of 34. After his death, his son Trisong Detsen succeeded him.

In 704 AD, the fourth ruler of Tibet, Chidai Zhudan, sent envoys to the Tang Dynasty to request a marriage alliance. In 707 AD, Emperor Zhongzong of Tang agreed to marry Princess Jincheng to him. In 710 AD, Princess Jincheng brought tens of thousands of bolts of brocade, various craft techniques, and a large number of artifacts to Tibet. In 733 AD, the Tang Dynasty and Tibet erected a boundary marker at Chiling (Huangyuan, Qinghai).

In 821 AD, the Tibetan King Tripajin sent envoys to Chang'an three times to request a meeting. Emperor Muzong of Tang ordered his prime minister and Tibetan officials to hold a grand meeting ceremony in the western suburbs of Chang'an. In 822 AD, the Tang Dynasty sent Liu Yuanding and others to Tibet, where they formed an alliance with the Tibetan monks Bochanbu and Shang Qixin'er in the eastern suburbs of Lhasa. This event is known as the "Changqing Alliance." The two sides reaffirmed their historical kinship of "harmony as one family," agreed to "remain united in the state," and erected a Tang-Tibetan alliance monument in front of the Jokhang Temple in Lhasa.

In 842 AD, the Tubo Dynasty was embroiled in internal strife within the royal family, leading to inter-tribal and inter-general conflicts. Subsequently, the dynasty began to split and disintegrate, with many local forces emerging throughout the Tibetan region, each occupying its own territory and waging war against each other.