The Tang Dynasty was a powerful Chinese empire that grew from China to expanding so far into Central Asia as to fighting in wars with Persia. The empire reached a level of Chinese wealth unseen until the rise of the Yang Dynasty after the collapse of the Mongol Empire. The might of the empire was not enough to restrain the Mongols from the mostly ignored northern frontier, but it was enough to weaken the empire to keep it from invading the Tibetan Empire. However, the empire established Buddhism as a major religion in Central Asia and is also seen as the empire that converted many Persians to Buddhism. Araxava and his empire existed because of this dynasty.