Sotheby's announced this week that one of its major sales of Asia Week New York will be a jade seal that was once owned by China's Qianlong emperor (1711-1799).
The spectacular but tiny seal is expected to sell for an impressive $1m-1.5m. Yet it is not the first of these seals to appear at auction, and given their popularity among the most discerning Asian collectors, it will certainly not be the last.
The first recorded reference to the usage of a seal in China was in 544 BC, at the beginning of the nation's Zhou dynasty, though the practice is thought to be centuries older.
The most important of these early seals was the Imperial Seal of China or Heirloom Seal of the Realm, which was carved out of the He Shi Bi, a famous piece of jade that plays a major role in many of China's historical stories. This seal was passed down through the dynasties before it was lost in the Five Dynasties and Ten Kingdoms Period (907-960).
All of China's emperors would have had at least one official seal, which could be used to give their approval on various documents. Artists and scholars also used private seals to mark their finished work, with some owning many different variations.
The Qianlong emperor was known to have selected 25 or more seals for his official use and, as a keen poet, artist and collector, had many more to show his appreciation of an artist's work, as was the tradition of the time. Many famous or esteemed collectors would add their seal to an existing piece to heighten its value or appeal in years to come.
The emperor had many different seals made to mark the important occasions in his life. For example, the seal selling at Sotheby's later this month was made to commemorate his 70th birthday, as one of China's longest ruling emperors.
Another, which made $3.4m at Asia Week in September 2012, was created to mark the emperor's 80th birthday, which was five years prior to his planned abdication, after 60 years on the throne. As such, the seal was inscribed with a phrase that reflected his concern for the empire once he had abdicated.
The current world record for any jade item at auction was set at Sotheby's in April 2010 by a white seal that marks the Qianlong emperor's abdication in 1796, which sold for an outstanding $12.2m.
However, not all of these sales are met with the same enthusiasm displayed by top collectors, with Chinese officials condemning the $1.4m auction of a Qianlong seal in December 2012. The seal had been looted as British and French troops invaded Beijing at the end of the second opium war (1856-1860), and many Chinese people feel that it should be returned to its native country.
This was also the case of a vase produced for the Qianlong emperor, which made global headlines in 2010 after it came under fire for the same reasons, yet was finally sold for $40m in January 2013.