Kingdom of Qocho in the context of "Bezeklik Thousand Buddha Caves"

Mahayana Buddhism entered Han China via the Silk Road, beginning in the 1st or 2nd century CE. The first documented translation efforts by Buddhist monks in China were in the 2nd century CE via the Kushan Empire into the Chinese territory bordering the Tarim Basin under Kanishka. These contacts transmitted strands of Sarvastivadan and Tamrashatiya Buddhism throughout the Eastern world.

Theravada Buddhism developed from the Pāli Canon in Sri Lanka Tamrashatiya school and spread throughout Southeast Asia. Meanwhile, Sarvastivada Buddhism was transmitted from North India through Central Asia to China. Direct contact between Central Asian and Chinese Buddhism continued throughout the 3rd to 7th centuries, much into the Tang period. From the 4th century onward, Chinese pilgrims like Faxian (395–414) and later Xuanzang (629–644) started to travel to northern India in order to get improved access to original scriptures. Between the 3rd and 7th centuries, parts of the land route connecting northern India with China was ruled by the Xiongnu, Han dynasty, Kushan Empire, the Hephthalite Empire, the Göktürks, and the Tang dynasty. The Indian form of Buddhist tantra (Vajrayana) reached China in the 7th century. Tibetan Buddhism was likewise established as a branch of Vajrayana, in the 8th century.

The Dharmaguptaka (Sanskrit: धर्मगुप्तक; Chinese: 法藏部; pinyin: Fǎzàng Bù; Vietnamese: Pháp Tạng bộ) is one of the eighteen or twenty early Buddhist schools, depending on the source. They are said to have originated from another sect, the Mahīśāsakas. The Dharmaguptakas had a prominent role in early Central Asian and Chinese Buddhism, and their Prātimokṣa (monastic rules for bhikṣus and bhikṣuṇīs) are still in effect in East Asian countries to this day, including China, Vietnam, Korea, and Japan as well as the Philippines. They are one of three surviving Vinaya lineages, along with that of the Theravāda and the Mūlasarvāstivāda.

Jimsar County is a county in Changji Hui Autonomous Prefecture, Xinjiang, China. It contains an area of 8,149 km (3,146 sq mi). According to the 2002 census, it has a population of 130,000.

Near the town of Jimsar are the ruins of the ancient city of Beiting (Chinese: 北庭; pinyin: Běitíng) or Ting Prefecture (Chinese: 庭州; pinyin: Tíngzhōu), the headquarters of the Beiting Protectorate during the 8th century. It was later known as Beshbalik (Chinese: 别失八里) and became one of the capitals of the Uyghur Khaganate and then the Kingdom of Qocho.

The Asud (Mongolian Cyrillic: Асуд, IPA: /ˈasʊt/) were a military group of Alani origin. The Mongol clan Asud is the plural of As, the Arabic name for the Alans.

Against the Alans and the Cumans (Kipchaks), the Mongols used divide and conquer tactics by first telling the Cumans to stop allying with the Alans and after the Cumans followed their suggestion the Mongols then attacked the Cumans after defeating the Alans. Alans were recruited into the Mongol forces with one unit called "Right Alan Guard" which was combined with "recently surrendered" soldiers, Mongols, and Chinese soldiers stationed in the area of the former Kingdom of Qocho and in Besh Balikh the Mongols established a Chinese military colony led by Chinese general Qi Kongzhi (Ch'i Kung-chih). Alan and Kipchak guards were used by Kublai Khan. In 1368 at the end of the Yuan dynasty in China Toghan Temür was accompanied by his faithful Alan guards. Mangu enlisted in his bodyguard half the troops of the Alan prince, Arslan, whose younger son Nicholas took a part in the expedition of the Mongols against Karajang (Yunnan). This Alan imperial guard was still in existence in 1272, 1286 and 1309, and it was divided into two corps with headquarters in the Ling pei province (Karakorúm). In 1254 Rubruquis found a Russian deacon amongst the other Christians at Karakoram. The reason why the earlier Persian word tersa was gradually abandoned by the Mongols in favour of the Syro - Greek word arkon, when speaking of Christians, manifestly is that no specifically Greek Church was ever heard of in China until the Russians had been conquered; besides, there were large bodies of Russian and Alan guards at Peking throughout the last half of the thirteenth and first half of the fourteenth century, and the Catholics there would not be likely to encourage the use of a Persian word which was most probably applicable in the first instance to the Nestorians they found so degenerated. The Alan guards converted to Catholicism as reported by Odorico. Alans were converted to Roman Catholic Christianity in addition to Armenians in China by John of Montecorvino.