One masterwork in Emperor Qianlong's collection. [Photo provided to China Daily]

Governing tool

One example is the Painting of Five Bulls from the Tang Dynasty (618-907), arguably one of China's 10 best historic paintings. Having designated a special building in the Forbidden City to house it, Qianlong treated the work more as a piece of religious iconography than a mere art treasure, Zhang says.

"He paid ritualistic visits to the painting every spring, when he conducted a farming ceremony to pray for a fertile new year. He did this without fail for 23 years."

Yang attributes Qianlong's unique role in Chinese art history to several things.

"He became emperor in 1736, exactly 100 years after the Qing Dynasty was founded. And it took all of a century for the chaos of the dynasty-changing wars to subside. Also, when the Ming Dynasty fell, all the precious art works of the royal collection were dispersed. For the next 100 years they kept changing hands, until they ended up with Emperor Qianlong."

The emperor's abiding interest in art was aided by his age as well as his wealth, Wang said. "Ascending to the throne early in life may have stunted his artistic growth－after all, no one is going to dare criticize an emperor－yet it gave Qianlong an easy confidence that befitted his role as his empire's foremost art patron and collector."

After him, the fortunes of Qing took a decided downturn. Invaders eventually came from the other side of the ocean. One hundred and twelve years after his death, the empire was replaced by a Republic. China was never the same, and the walls of the Forbidden City proved to be much less impregnable than the powerful leader had believed.