Woodblock printing was developed in the early Tang era with examples of its development dating to around 650 A.D. More common use is found during the ninth century, with calendars, children’s books, test guides, charm manuals, dictionaries and almanacs. Commercial books began to be printed around 762 B.C. In 835 B.C. there was a ban on private printing brought on because of the distribution of unsanctioned calendars. The oldest surviving printed document from the Tang era is the Diamond Sutra from 868 A.D., a 16-foot scroll featuring calligraphy and illustrations.