A Chinese Qing dynasty seal is to provide the star lot at Sotheby's first sale of New York's Asia Week, which will take place on March 19-20.
As the event gets underway, the Qing dynasty jade seal is expected to realise $1-1.5m. It is one of several such pieces made to celebrate important events in the life of the Qianlong emperor (1711-1799).
The seal was recently discovered in Washington State, having been passed down through the family of the current owner from his grandfather, a US brigadier general who held several senior positions in Europe during and after the second world war. The family had been unaware of its value until consulting Sotheby's.
This is the largest and one of the most important seals produced for the emperor. During the 1780s, the emperor commissioned a large series of seals to mark his 70th birthday, each with the inscription "Guxi Tangzi", meaning "seal of the 70 year old son of heaven".
This inscription was added to three years later when his first great-great-grandson was born, so that it would read "Wufu Wudai Tang Guxi Tiaxi Bao", which translates to "Seal of the 70 year old son of heaven at the hall of five happiness' and five generations".
In September 2012's Asia Week sales, another Qianlong jade seal sold at Sotheby's, achieving an outstanding 191.5% increase on its $1.2m high estimate to sell for $3.4m.