Cai Lun(48 — 121)
Cai Lun
dynastie Han
8 min read
An official at the imperial court during the Han dynasty, Cai Lun is credited with inventing paper in 105 AD. He refined a process using plant fibers, bark, and rags to produce a lightweight and inexpensive writing material.
Key Facts
- 105 AD: official presentation of paper to Emperor He of Han
- Use of recycled materials (rags, fishing nets, bark) to make paper
- The process spread across Central Asia and then into Europe via the Silk Road
- Deified after his death in certain Chinese artisan traditions
Works & Achievements
Cai Lun refined a process for making paper from plant fibers, mulberry bark, hemp, and rags, and officially presented it to the Emperor. This standardization of paper would permanently transform written communication throughout the world.
As director of the imperial workshops (Shang Fang), Cai Lun oversaw improvements to forging techniques and the manufacture of court objects. Han texts credit him with raising the quality of imperial craft production.
An official document presented to Emperor He describing the materials, process, and advantages of the new medium. This report, mentioned in the *Hou Han Shu*, is the founding act of the invention's official recognition.
With imperial backing, Cai Lun organized the dissemination of the process across the empire's provinces. This sweeping administrative adoption made paper the dominant medium, gradually replacing bamboo and silk.
Anecdotes
Cai Lun was a court eunuch who climbed the ranks of the Eastern Han imperial hierarchy to become director of the imperial workshops. This position gave him access to the artisans and materials needed to conduct his experiments on new writing surfaces, at a time when bamboo and silk still dominated.
In 105 CE, Cai Lun officially presented his paper to Emperor He of the Han dynasty. He had experimented with a mixture of mulberry bark, hemp, old rags, and worn fishing nets, soaked in water and then dried on frames. The emperor was so impressed that he ordered the technique to be disseminated throughout the empire.
In tribute to its inventor, the new paper was quickly nicknamed 'Cai Hou Zhi' (蔡侯纸), meaning 'paper of Marquis Cai.' Cai Lun had indeed been granted the title of Marquis of Longting in recognition of his services at court. This name remained in use for centuries in Chinese texts to denote high-quality paper.
Cai Lun's final years were tragic. Caught up in court intrigues during the reign of Emperor An of Han, he was accused of having once taken part in a plot against the imperial family. Rather than face a humiliating trial, he drank poison after dressing himself in his ceremonial robes. This episode illustrates the precariousness of power at the Han court.
For a long time, archaeologists debated whether Cai Lun had truly invented paper or merely improved upon an existing technique. Excavations carried out in China during the 20th century uncovered paper fragments predating Cai Lun, dating to the 2nd century BCE. His true contribution therefore appears to have been industrializing and standardizing the manufacturing process, turning paper into an accessible and reliable writing surface.
Primary Sources
Cai Lun, whose courtesy name was Jingzhong, was a native of Guiyang. [...] He submitted to the Emperor a report on the manufacture of paper from tree bark, hemp, old rags, and fishing nets. The Emperor acknowledged his merits, and from that time on everyone used this paper, which became known throughout the world as 'the paper of Marquis Cai'.
In the fourteenth year of the Yuanxing era (105 AD), Cai Lun presented to the throne paper made from mulberry bark, hemp, rags, and fishing nets. The Emperor approved it and ordered its dissemination.
The imperial workshops supplied the court with writing materials, notably bamboo tablets and silk scrolls. The cost of silk made administrative correspondence extremely expensive for the state.
Paper has its origins in bamboo bark, hemp, rice straw, and reeds. The craftsman soaks the fibers, beats them, spreads them on a frame, and leaves them to dry. It was Cai Lun who first brought these techniques together and refined them.
Key Places
Presumed birthplace of Cai Lun. This region of southern China was rich in bamboo and hemp, raw materials that played a role in his experiments with plant fibers.
The imperial capital where Cai Lun spent most of his career at court. It was in the imperial workshops of Luoyang that he conducted his research and presented his invention to Emperor He in 105 AD.
A palatial institution in Luoyang that Cai Lun came to direct. These workshops produced weapons, tools, and prestige objects for the court; it was here that Cai Lun was free to experiment with new materials.
The site of the traditional tomb attributed to Cai Lun, venerated as a memorial by papermakers. Ceremonies in his honor were still held there during the medieval period.
The trade network that enabled the gradual spread of Han paper westward into Central Asia, Sasanian Iran, and the Arab world. The Battle of Talas (751) accelerated this transmission toward the West.