FACTBOX: Historical ties between China and Tibet

(Reuters) - At the heart of the conflict over Tibet's status within China is their historical relationship.

The Chinese government and Tibet's government-in-exile offer competing versions of whether the remote, mountainous territory was historically ruled as part of China, or whether it has legitimate claims to independence or autonomy.

Following are some details about the history of relations.

THE IMPERIAL ERA

- Most historians agree that Tibet's assimilation into China was established during the Yuan dynasty (1271-1368). In China's view, the relationship continued throughout the next two dynasties, the Ming and the Qing.

But the nature of relations are complicated by several factors:

- During the Yuan dynasty, both China and Tibet were ruled by the Mongols under Kublai Khan. The Qing dynasty (1644-1911) was similarly a period of foreign rule, under the Manchus. Some argue that during these periods Tibet was not ruled by China, but that both were ruled as part of a foreign empire.

- The relationship between China and Tibet varied over the centuries depending on the relative strength or weakness of the imperial government. The Qing emperors were especially weak towards the end of their reign, when British and other foreign forces began making inroads.

- Some say that over these centuries the relationship of Tibet to China is best described as that of a vassal state, but there are disputes over the nature of the priest-patron ties and whether Tibet was viewed as subordinate.