Du You
Du You had been impressed by a 35-volume work by Liu Zhi during Emperor Xuanzong's reign known as the "Zhengdian", which was a compendium of philosophies, rites, and principles of governance. However, Du considered the "Zhengdian" to be incomplete, so he expanded on the coverage of the "Zhengdian" and added writings about the rites, music, and written works of Emperor Xuanzong's time, into a 200-volume work. In 801, while he was still at Huainan, he had his subordinates carry the work to Chang'an to offer it to Emperor Dezong. Emperor Dezong issued an edict greatly praising the work. The work became popular and a key source of information on rites, music, criminal law, and governance for the people of the time, and it was said that it was so detailed that the information from the last thousand years could be accessible easily.