Invention of Paper in China: Cai Lun and the Han Papermakers

Paper was invented in China during the Han dynasty, and in AD 105 a palace official named Cai Lun presented an improved papermaking process to Emperor He at Luoyang. Although archaeology shows that paper existed at least two centuries earlier, Cai Lun’s method helped make it a practical, affordable writing material. From China the craft spread across Asia and the Islamic world to Europe, transforming how knowledge was recorded and shared.

The traditional story credits Cai Lun alone, and in China he is still honoured as the patron of papermakers. The real history is longer and more interesting, involving anonymous Han craftsmen, centuries of slow improvement and a journey across the whole of Eurasia.

Writing before paper

Before paper, Chinese scribes wrote mainly on narrow strips of bamboo or wood, which were tied together with cord into rolls. They were cheap but heavy and bulky. A famous anecdote says that the First Emperor of Qin read 120 jin, about 30 kilograms, of documents each day.

The other option was silk, which was light and easy to write on but expensive. The Han tombs at Mawangdui, sealed in the second century BC, contained both bamboo-slip and silk manuscripts. Elsewhere in the ancient world people used papyrus, parchment, palm leaves and clay tablets.

True paper is different from all these. It is a thin sheet made from plant fibres that have been broken down in water and then matted together on a screen as the water drains away.

Paper before Cai Lun

Excavations in China since the 1930s have found many fragments of paper older than AD 105:

• Baqiao (Xi’an), found in 1957: fragments of coarse hemp paper from a tomb usually dated to the second century BC, although the dating has been debated.
• Fangmatan (Gansu), found in 1986: a small paper fragment with lines that appear to form a map, from a tomb dated to the early Western Han, roughly the second century BC.
• Xuanquan (near Dunhuang, Gansu): hundreds of paper fragments from a Han postal station, some carrying written characters and dated from the first century BC onwards.
• Lop Nor (Xinjiang), found in 1933: a fragment from a context with a wooden slip dated 49 BC.

Much of this early paper was rough and may first have been used for wrapping and padding, including wrapping medicines and bronze mirrors. Some pieces, however, carry writing, which shows that paper was already being used as a writing surface before the Eastern Han.

Cai Lun’s process of AD 105

Cai Lun (died AD 121) was a eunuch who served in the palace from the 70s AD. Under Emperor He he became Director of the Imperial Workshops (shangfang ling), responsible for making weapons, tools and luxury goods for the court.

According to his biography in the Book of the Later Han, writing on silk was costly and bamboo was heavy, so Cai Lun devised a way of making paper from tree bark, hemp waste, old rags and fishing nets. In AD 105 he presented the method to the emperor, who praised it, and from then on paper came into general use. People called it “Marquis Cai’s paper” after he was made Marquis of Longting in AD 114.

His real achievement was probably to improve and standardise an existing craft rather than to invent it. Using cheap waste materials such as rags and nets, and adding tree bark, likely from the paper mulberry, increased supply and lowered cost. The imperial workshops also gave the method official backing and a route to wider use.

Cai Lun’s career ended in tragedy. He had been involved in palace intrigue under the Empress Dou, and when Emperor An began ruling in his own right in AD 121 he ordered Cai Lun to answer for his past conduct. Cai Lun took poison instead.

How Han paper was made

The basic method, which changed little for centuries, can be summarised in five steps:

1. Preparing the fibres: hemp, rags, nets or bark were soaked and cut up, then boiled with wood ash or lime to loosen the fibres.
2. Beating: the material was pounded in a mortar until it broke down into a wet pulp.
3. Forming the sheet: the pulp was mixed with water in a vat, and a screen in a frame was dipped in and lifted out, leaving a thin even layer of fibres.
4. Pressing and drying: the wet sheets were pressed and then dried on walls or boards in the sun.
5. Finishing: sheets could be smoothed, sized or dyed for better writing.

Later Han craftsmen continued to improve paper. Zuo Bo, a scholar of the late second century AD, was famous for making especially fine paper. By the fourth century AD paper had largely replaced bamboo and wood for books and documents in China.

The spread of papermaking

Paper moved outwards from China slowly, usually carried by monks, merchants and craftsmen:

• Korea and Japan: papermaking probably reached Korea by around the fourth to sixth centuries AD, although the date is uncertain, and the Japanese chronicle Nihon Shoki records that the Korean monk Damjing introduced papermaking materials to Japan in AD 610.
• Central Asia: paper documents were common along the Silk Road routes by the fourth century AD.
• The Islamic world: Samarkand became a famous papermaking centre, and a paper mill was established in Baghdad around 794–795, a development covered in Papermaking in Abbasid Baghdad. Paper spread to Syria, Egypt and North Africa.
• Europe: paper was made in Muslim Spain, notably at Xàtiva, by the twelfth century. Italian mills at Fabriano were active by the 1270s, and Ulman Stromer founded a paper mill at Nuremberg in 1390. England’s first known mill was set up by John Tate near Hertford in the 1490s.
• The Americas: paper was being made in Mexico by the 1570s and near Philadelphia, at the Rittenhouse mill, from 1690.

Consequences

Cheap paper changed government, religion and learning. Chinese bureaucracy could keep larger records, and Buddhist monasteries copied huge numbers of scriptures. Paper made woodblock printing practical; the Diamond Sutra of 868 is the oldest dated printed book to survive. In Song China paper was even used for money.

In Europe, paper’s arrival came just in time for the Gutenberg printing press of the mid-fifteenth century. Printing on parchment was possible but expensive, and cheap paper made mass-produced books and pamphlets affordable.

Key people

• Cai Lun (died AD 121): palace eunuch and Director of the Imperial Workshops, credited in the official history with the improved process of AD 105.
• Emperor He of Han (reigned AD 88–106): the ruler to whom Cai Lun presented his method, shortly before the emperor’s death.
• Empress Deng Sui (AD 81–121): Emperor He’s empress and later regent, under whom Cai Lun was ennobled. Her biography records that she preferred paper and ink to costly tribute items.
• Zuo Bo (late 2nd century AD): scholar and calligrapher remembered for producing paper of unusually high quality.
• Unknown Western Han craftsmen: the makers of the earliest surviving paper, whose names were never recorded.

Behind these few named figures stood many unrecorded workers in workshops across the empire. Papermaking was a skilled trade passed on within families and guilds, and regional traditions grew up around local fibres: bamboo paper in the south, mulberry-bark paper in many areas and rattan paper in Zhejiang under the Tang.

Myths and facts

• Myth: Cai Lun invented paper in AD 105. Fact: Paper is attested archaeologically from the Western Han, at least two centuries earlier; Cai Lun improved the process and gave it official status.
• Myth: Papyrus was an early form of paper. Fact: Papyrus is made from strips of the papyrus plant laid crosswise and pressed, not from pulped fibres, so it is a different technology, although the word “paper” comes from it.
• Myth: Chinese prisoners from the Battle of Talas in 751 brought papermaking to the Islamic world. Fact: The story appears in later Arabic sources, but paper was already known in Central Asia before 751.

By the numbers

Timeline

• c. 2nd century BC: Hemp paper is made in Western Han China (Baqiao and Fangmatan finds).
• 49 BC: Approximate date of the Lop Nor paper fragment.
• AD 105: Cai Lun presents his improved papermaking process to Emperor He.
• AD 114: Cai Lun is made Marquis of Longting.
• AD 121: Cai Lun dies by poison after falling from favour.
• AD 610: Papermaking reaches Japan, according to the Nihon Shoki.
• c. 794–795: A paper mill is set up in Baghdad.
• 12th century: Paper is made at Xàtiva in Spain.
• 1390: Ulman Stromer opens a paper mill in Nuremberg.

Why it matters

Paper is one of China’s most important gifts to the world. By making writing cheap and portable, it supported bureaucracies, religions, scholarship and later printing, and for nearly two thousand years it was the main material on which human knowledge was recorded.