Political Structure
The Uighur Khaganate was a tribal confederation ruled by a Khagan, or emperor. The Khagan was elected by the tribal chiefs and had absolute power over the empire. The empire was divided into provinces, each governed by a governor appointed by the Khagan.
The Tibetan Empire, on the other hand, was a centralized state ruled by an emperor. The emperor was considered to be the divine embodiment of Avalokiteshvara, the bodhisattva of compassion. The empire was divided into provinces, each governed by a viceroy appointed by the emperor.
Religion
The Uighur Khaganate embraced Manichaeism, a dualistic religion that originated in Persia. However, the Uighurs were also tolerant of other religions, such as Buddhism and Christianity.
The Tibetan Empire, on the other hand, was a staunchly Buddhist state. Buddhism was introduced to Tibet in the 7th century and quickly became the dominant religion. The emperor was considered to be the protector of Buddhism and played an active role in promoting the religion.
Military
The Uighur Khaganate was a formidable military power. The Uighurs were skilled horsemen and archers and were known for their use of heavy cavalry. The Uighurs also had a strong navy, which allowed them to control the trade routes in the Caspian Sea and the Aral Sea.
The Tibetan Empire was also a powerful military force. The Tibetans were skilled infantrymen and archers and were known for their use of mountain warfare tactics. The Tibetans also had a strong cavalry, but they were not as powerful as the Uighurs at sea.
Decline
The Uighur Khaganate declined in the 9th century after a series of wars with the Mongol Empire. The Tibetan Empire also declined in the 9th century after a series of civil wars. Both empires were eventually conquered by the Mongols in the 13th century.