1. The earliest paper in the world appeared in the Western Han Dynasty in China, which was rough in texture and could not be used for writing. After the improvement of Cai Lun in the Eastern Han Dynasty, plant fiber paper was made, which was light and cheap, reached the writing level and was widely used. This kind of paper is called "Cai Hou Paper".

2. The earliest paper in the world appeared in the Western Han Dynasty in China. The paper unearthed from the Han Tomb in Fangmatan, Tianshui, Gansu, China in the early Western Han Dynasty (206 BC-23 AD) is the earliest paper ever discovered. In addition, ancient paper of the Western Han Dynasty was also unearthed at the beacon tower site in Maquanwan, Dunhuang and the Han Xuanquan Post site in Xiangjing, Dunhuang. But these papers are rough and of poor quality, so they can't be used for writing.

3. The paper made by working people in the Western Han Dynasty was improved by Cai Lun in the Eastern Han Dynasty, and the paper made of plant fiber reached the practical level of writing, which was called "Cai Hou Paper". For Cai Lun, the purpose of improvement is to replace the writing and recording materials such as wooden slips, bamboo slips and silks. Because of the advantages of light weight and low price, paper has been widely used and become the main writing material. Papermaking can be said to be the greatest invention in human history! Because of the appearance of papermaking, culture can be better passed down, the weight of bamboo slips can be thrown away, and people can acquire knowledge in light books.