to written by someone ordered to do so by the Emperor. In the case of the Qing dynasty period Qianlong Emperor, who was known for his literary ambitions, including his ability to write in well-renowned calligraphy, had produced a large amount of texts which were affixed with the seal to indicate that they were his own writing. When the calligraphy of the Qianlong Emperor was carved into stone steles, the print of the seal was also copied onto the stone surface. Engraving types Zhuwen () seals imprint the Chinese characters in red ink, sometimes referred to as yang seals. Baiwen () seals imprint the background in red, leaving white characters, sometimes referred to as yin seals. Zhubaiwen Xiangjianyin () seals use zhuwen and baiwen together Government authorities National government The Chinese emperors, their families and officials used large seals known as xǐ (), later renamed bǎo (; treasure'), which corresponds to the Great Seals of Western countries. These were usually made of jade (although hard wood or precious metal could also be used), and were originally square in shape. They were changed to a rectangular form during the Song dynasty, but reverted to square during the Qing dynasty. The most important of these seals was the Heirloom Seal of the Realm, which was created by the first Emperor of China, Qin Shi Huang, and was seen as a legitimising device embodying or symbolising the Mandate of Heaven. The Heirloom Seal was passed down through several dynasties, but had been lost by the beginning of the Ming dynasty. This partly explains the Qing emperors' obsession with creating numerous imperial seals - for the emperors' official use alone the Forbidden City in Beijing has a collection of 25 seals - in order to reduce the significance of the Heirloom Seal. These seals typically bore the titles of the offices, rather than the names of the owners. Different seals could be used for different purposes: for example, the Qianlong Emperor had a number of informal appreciation seals () used on select paintings in his collection. The most popular style of script for government seals in the imperial eras of China (from the Song dynasty to Qing dynasty) is the Nine-fold Script (), a highly stylised script which is unreadable to the untrained. In its 143 years of existence, the government of the Nguyễn dynasty had created more than 100 imperial seals. According to