Cai Lun, an imperial court official and scientist during the Eastern Han Dynasty, invented paper, a material that would prove useful in communications and in many other ways.

Cai Lun was born in Guiyang (Kuei-Yang), present-day Chenzhou City in Hunan Province. There is little information about his early life. Historical records show that in 75 c.e., he entered the service of the imperial palace and became a liaison official with the privy council and chamberlain to the royal family. Later, he became the chief eunuch under Emperor He (Liu Zhao; r. 88-105/106 c.e.) of the Eastern Han Dynasty (25-220 c.e.). Cai Lun held the high position of minister in charge of imperial edicts and documents and was adviser to the emperor on state affairs. The emperor also appointed him chief of the Imperial Supply Department and put him in charge of making swords and furniture for the royal household. Cai Lun was also assigned curatorial responsibility for the Imperial Library. Cai Lun

In the thirteenth year of his reign, the emperor inspected the library and directed Cai Lun to organize piles of heavy wooden board books that were rarely used. At this time, Cai Lun began research to find a lighter material for books because the large, heavy volumes were cumbersome and difficult to move and store. His research and experimentation resulted in the invention of paper, the most significant achievement in the evolution of writing materials.

Around 4000 b.c.e., the ancient Egyptians had invented papyrus, the first paperlike substance. Papyrus was a laminated substance made of thin reeds pasted together. Later, ancient western Semitic peoples and the ancient Greeks wrote on parchment made from animal skins. In China, during the Shang Dynasty (1600-1066 b.c.e.), written records consisted of inscriptions on animal bones and tortoise shells. The inscribed bones recorded important information about agricultural methods, natural phenomena, imperial life, and other events. Oracle bones were used in divination ceremonies. During the Zhou Dynasty (1066-256 b.c.e.), Chinese characters were written or cast on bronze objects such as incense burners, bells, and cooking pots. However, this process was complicated, and the bronze was expensive, so it was impractical for general use. Later, around 600 b.c.e., people carved words on wooden and bamboo strips, which were then strung together with strings to form books. These books were bulky and heavy. In 250 b.c.e., the camelhair brush was invented in China, and the art of calligraphy and the use of woven cloth to make books and scrolls advanced quickly. Silk cloth became the main writing surface, but it was expensive.

Cai Lun realized the need for a completely new writing surface that would be cheaper and more convenient than silk and more practical than wood or bamboo. It is believed that he must have observed the silk-bleaching process and realized that any material that could be beaten into fiber could be used to make a writing surface. He developed a new process, which is still used to make paper. For raw materials, he used old fish nets, mulberry bark, hemp, and rags. He cut the ingredients into small pieces and then mashed them into a paste or pulp. Then these fibers were intermixed with water. This thin layer of pulp was dried on a piece of fine cloth, which served as a sievelike screen through which the water could drain. When dried completely, these thin layers of intertwined or matted fiber became paper. This writing material was thin, light, durable, and inexpensive to produce. It was a much better-quality writing surface than bamboo, wood, or silk. About 105 c.e., Cai Lun officially presented his discovery to the emperor, who praised him for this accomplishment. Cai Lun’s paper and his paper-making process immediately became popular in China.

In 106 c.e., after Emperor He died, he was succeeded by the infant emperor Shang (Liu Long), who died in his second year. Then Emperor An (Liu Shu) came to power in 107, with the dowager empress Deng (Teng) ruling for him. Cai Lun was named a lord or marquis in 114. After the empress died in 121, her enemies convinced Emperor An that the empress’s relatives and supporters were plotting against him. After being accused in this plot and receiving an imperial summons to court, Cai Lun committed suicide by drinking poison in 121. (The exact year of his death, however, is not mentioned in the historical records.) After his death, people named his invention the “paper of Cai Lun,” the “paper of Cai,” or the “paper of Marquis Cai,” in honor of his great achievement.

Cai Lun’s method of paper making was widely used in China and eventually became known outside China. In 751 c.e., Chinese paper makers were captured by Arabs after a battle, and the art of paper making was introduced in the Middle East. In the twelfth century, the Europeans learned the techniques from the Arabs. Paper making eventually spread to the rest of the world, and paper became the principal writing material in the West. Thus, Cai Lun’s invention eventually had a worldwide impact on communications and the preservation of human knowledge.

The technique for making paper today is still the method developed by Cai Lun. Today, paper is used not only as a medium in communications and writing but also as a component in home construction materials, health and beauty products, agricultural products, packaging, and many other products.

• Hunter, Dard. Paper Making: The History and Technique of an Ancient Craft. New York: Dover Publications, 1974. Includes a chapter titled, “Ts’ai Lun and the Invention of Paper: The Influence of Calligraphy Upon Paper and the Influence of Paper Upon Printing.” Illustrated. Also includes a “Chronology of Paper and Allied Subjects.”
• Laufer, Berthold. Paper and Printing in Ancient China. New York: B. Franklin, 1973. Includes information on the history of paper making in China.
• Narita, Kiyofusa. A Life of Ts’ai Lung and Japanese Paper-Making. Tokyo: The Paper Museum, 1980. Discusses the introduction of paper making in Japan by way of Korea in 610 c.e. Illustrated.
• Tanenbaum, Mary, ed. Chinese Book Arts and California. San Francisco: Book Club of California, 1989. Although this limited edition is not easy to come by, it offers a rare illustrated overview of the Chinese book arts–not only in California but also in China. Includes an essay, “Papermaking in China,” by Söören Edgren.
• Veilleux, Louis. The Paper Industry in China from 1949 to the Cultural Revolution. Toronto: University of Toronto-York University, Joint Centre on Modern East Asia, 1978. A rare history of Chinese papermaking, with maps.
• Zhong, Shizu. Ancient China’s Scientists. Hong Kong: Commercial Press, 1984. Includes a chapter about Cai Lun. English-Chinese glossary of Chinese terms. Illustrated.