Li Chun (778-820)Li Chun (778-820) - Also known as Emperor Xianzong, he was the last significant emperor of the Tang Dynasty, and Li Longji's great-great-great grandson.  Significant because he came to power when the empire was in steep decline and breaking up into feudal kingdoms under the control of local lords. Emperor Xianzong made an attempt to reunite all of China under his rule.  When the feudal lords resisted, he went to war against them.  He began his campaign in 806, and after 11 years, succeeded in bringing the whole country under imperial authority in 817.  Today, historians refer to this reunification as the Yuanhe Restoration.  But the triumph was short-lived.  The return of imperial power saw also the return of imperial politics, and Emperor Xianzong was murdered (supposedly) by a court eunuch named Chen Hongzhi in 820.  His successor, Emperor Muzong, was too weak to maitain the empire, and it soon began to fracture again.  Even though it limped along for another century, the eventual downfall of the Tang Dynasty was inevitable.