The Invention and Global Spread of Paper

Cai Lun, a eunuch official at the Han court, presented Emperor He with a papermaking method around 105 CE: soaking and pounding tree bark, hemp waste, old rags, and fishing nets into a pulp, then drying thin, even sheets on bamboo screens. Archaeologists have since found earlier evidence: in 1986, a paper fragment excavated at Fangmatan, in Gansu province, was dated to roughly 179-141 BCE, more than two centuries before Cai Lun's report. The material was cheaper than silk, lighter than bamboo strips, and more consistent than earlier attempts, and the emperor praised it. Cai Lun is traditionally credited as paper's inventor, though the Fangmatan fragment shows he refined and standardized an existing craft rather than creating an entirely new one from scratch.

After the Abbasid Caliphate defeated Tang forces at the Battle of Talas in 751 CE, papermaking took hold in Samarkand. The popular story credits Chinese prisoners of war, but historian Jonathan Bloom calls it unlikely to be factual, since archaeological finds show paper was already in use there decades before the battle.

By the end of the 8th century, paper mills were operating in Baghdad, the Abbasid capital. Unlike parchment or papyrus, paper could be produced locally wherever water was available, making it dramatically cheaper. Baghdad's paper supply underpinned the translation movement and libraries later idealized as the House of Wisdom.

The first recorded paper mill on the Iberian Peninsula operated at Xàtiva, near Valencia, using the Albaida River for water power and local flax fields for fiber. Historians place its founding anywhere from 1056 to the mid-12th century; the 12th-century geographer al-Idrisi wrote that Xàtiva's paper was unmatched anywhere in the civilized world and was exported east and west. Papermaking in Europe stayed concentrated in Islamic Iberia for roughly two centuries before spreading into Christian territory.

Paper mills established at Fabriano, in central Italy, around 1276 introduced two lasting improvements over the Islamic-world process they inherited: mechanical stamping hammers, powered by waterwheels, that pulped rags faster and more finely than hand-beating, and sizing with animal glue, which let ink sit on the surface rather than bleed through. Within about six years, Fabriano's makers began pressing wire designs into the pulp mold, creating watermarks.

Nicolas-Louis Robert, a clerk tired of managing quarreling workers at a French paper mill, patented a machine in January 1799 that formed paper as an unbroken sheet on a moving belt of wire cloth, rather than one page at a time dipped by hand from a vat. Robert lost control of his own patent in a financial dispute, and English financiers, the Fourdrinier brothers, funded its refinement into what's still called the Fourdrinier machine today.

For nearly 1,700 years, paper needed rags, old rope, or worn-out fishing nets as raw material, a supply that couldn't keep pace with a growing population. In 1844, Saxon inventor Friedrich Gottlob Keller completed a machine that ground wood into a pulp fine enough for papermaking. Canadian inventor Charles Fenerty developed a similar process independently around the same time. Keller sold his invention for roughly £80, but wood-pulp paper could be produced at industrial scale, driving down the price of paper enough to make cheap newspapers and mass-market books possible.