The Empire of Tibet was one of the major powers struggling for control and influence in central Asia from the 7th to the 9th centuries. Over the years Tibet was in conflict with China and the Arabs. The tides of influence ebbed and flowed, often as a result of warfare and political alliances forged to check one great power or another. This story opens in the year 756-757 AD, when the T’ang Chinese influence over the trade-rich Tarim Basin was on the wane.

As the T’ang withdrew their garrison troops to quell the internal rebellion of An Lu Shan, a new “Boy Emperor” comes to power in Tibet.

Born in the year 740, the Emperor Trisong Detseng became known as one of the three great “Dharma Kings” of Tibet. Under his reign Tibet began to expand into the western provinces of the Tarim Basin, and east towards China itself. As a corollary to this effort, Trisong Detseng invited the Indian holy man Padma to the imperial court, where he supported the interpretation of a new offshoot of Buddhism as Tibet’s “official” state religion. This move created conflict with both the older Bon Po priests of Tibet and the T’ang Chinese Hinayana Buddhist monks that had infiltrated Tibet over the years. Thus Trisong Detseng began to wage war on the T’ang along both religious and military/political fronts.

Militarily,  Tibet’s initial aim was to roll back the fortress lines built by the Chinese General Koso Khan along their eastern border. The campaign was aided by a Tibetan alliance with the native peoples of this region. Secondly, Tibet aimed to isolate and weaken the T’ang empire by cutting off the rich trade routes leading into China from the west. To accomplish this, Tibet began to slowly re-occupy the Tarim Basin.

The armies of Tibet were more than a match for the T’ang generals under normal circumstances. Tang dynasty often relied on foreign generals and an infusion of mercenary troops from her outlying provinces. Now, with the Tang army distracted by the An Lu Shan rebellion, Tibet was eventually able to cut off the remnant of the Tang garrisons in the Tarim Basin. They pushed so far that they actually occupied the capital of Tang, Chang’an, for a brief period, installing their own puppet emperor there!