Cai Lun (蔡伦) and the Ancient Chinese Invention of Paper: Lessons for Modern Innovators

Among the many inventions that came from ancient China, four in particular have been given attention for their impact on the modern world. Known today as the “Four Great Inventions” (四大发明; or “si da fa ming”), they are:

1. The Compass
2. Gunpowder
3. Papermaking
4. Printing

Who can overestimate the profound impact of the last two intertwined inventions on our world today? But providing the proper credit for these ancient inventions is a difficult task. Today, though, I wish to honor the Chinese innovation of paper by giving attention to one of its foremost ancient champions.

As Dard Hunter wrote in his classic book on the history of paper (Papermaking: The History and Technique of an Ancient Craft, New York: Alfred A Knopf, 1943), the development of most crafts, including papermaking, are enshrouded in mystery. Nevertheless, the best information we have points to a servant of the Chinese imperial court, a eunuch named Cai Lun (sometimes spelled Ts’ai Lun), as the man who should be or at least can be credited with the innovation of paper in 105 A.D. This was during the height of the Han Dynasty (202 BC-AD 220, more specifically the Eastern Han Dynasty, AD 25–220), one of several golden eras of Chinese history.

I choose my words carefully when I speak of the innovation and not necessarily the invention of paper. The invention–the original creation of a web made from macerated, individual fibers laid down in a slurry on a porous support such as a wire or cloth–may have been by someone else. There is archaeological evidence of paper made from hemp decades earlier, and there is the probability that in Cai Lun’s day, others working for him devised or improved the papermaking process that has long been associated with his name. But Cai Lun took paper beyond being a technical invention and helped drive its widespread adoption such that it became a successful innovation, one that would stick and change the world for centuries to come.

The history of innovation teaches us that a single inventor is rarely responsible for a noteworthy invention, especially one that dramatically changes the world for good. A long list of people may have contributed knowledge and advances to the creation of paper in Cai Lun’s day, with many thousands having done the same since his time to give us the brilliant spectrum of products and processes we now know.

In the fifth century, the Chinese scholar Fan Ye credited Cai Lun (蔡伦) with the discovery of paper in his official history of the Han Dynasty. He writes that Cai Lun, a highly regarded eunuch in the Imperial Court, applied his talents to solve the problem of making writing more convenient. Writing and inscriptions were done on bamboo or silk strips, but these were not convenient materials to work with and silk was costly. Fan Ye credits Cai Lun with having “conceived the idea of making paper from the bark of trees, hemp waste, old rags, and fish nets.” Perhaps he was the originator, the one who conceived of and invented paper, or rather, reinvented or improved what others had tried earlier. Perhaps he had a vision for improving a prototype material and the method of making it, and gave directions to his staff for the trials to run to obtain breakthrough improvement. In any case, Fan Ye indicates that he and his crew conducted research on this topic, made significant advances, and then, importantly, made a report to the Emperor that was highly regarded and gained support.

The China Internet Information Center (China.Org.Cn) reports that when Cai Lun presented his first batch of paper to the Han emperor, the emperor was so delighted that he named the material “Marquis Cai’s paper.” In 1974, archaeologists found Eastern Han Dynasty paper found in Wuwei with written words that were still clearly decipherable. “Thin, soft, and with a smooth finish and tight texture, this paper is the most refined and oldest paper discovered to date.” [This may exclude some older cruder specimens.]

In addition to Cai Lun’s technical advances, his report to the Emperor may have been a crucial step in driving the social adoption of paper, resulting in its widespread use. According to Fan Ye, after he submitted his work to the Emperor, he “received praise for his ability. From this time, paper has been in use everywhere and is universally called 'the paper of Marquis Cai.” Paper was about to become more than a rare find in future archaeological digs, but a universally used medium that would change the world for centuries, even millennia to come.

Many inventions wither away into obscurity and fail to become lasting innovations until the right person with the right vision, means, and connections comes along and breathes life and fullness into the concept. Cai Lun, with access to the Emperor, with a vision of the potential of the invention, and with the credibility and track record to make a report that would gain imperial attention and support, was such a man. It is Cai Lun whom we can properly credit for successfully driving the innovation of paper into ancient Chinese and ultimately world history, regardless of how much of the actual inventing was done by him.

Cai Lun was born in Guiyang (modern day Leiyang). He served as a court eunuch since AD 75, was then promoted several during the time of Emperor He of the Han Dynasty. Around AD 97, he would distinguish himself and his men through his highly skilled work in producing swords and other weapons that served as models for future weapons production.

After his success with paper, he was praised and rewarded with the taxes from three hundred dwellings and became a chief in the palace. He was also trusted in correcting some important written histories.

Unfortunately, Cai Lun became involved in imperial intrigue, assisting the Empress in dealing with a romantic rival for the Emperor’s attention. When power shifted in AD 121, he was called to be judged for his role. Rather than appear for judgment, Cai Lun bathed, dressed in his finest robes, and then drank poison, ending the life of the great innovator whom we can honor for one of the most important inventions in the history of civilization.