 Even as late as 1733, a 2300-volume "Wuying Palace Collected Gems Edition" (《武英殿聚珍版叢書》) was printed with 253,500 wooden movable types on order of the Qianlong Emperor, and completed in one year.A number of books printed in Tangut script during the Western Xia (1038–1227) period are known, of which the Auspicious Tantra of All-Reaching Union that was discovered in the ruins of Baisigou Square Pagoda in 1991 is believed to have been printed sometime during the reign of Emperor Renzong of Western Xia (1139–1193).It is considered by many Chinese experts to be the earliest extant example of a book printed using wooden movable type.