Around 750, just before the Umayyads were overthrown in Damascus, there was a battle at the far eastern front. It was like any other battle, but it was so close to the Chinese border that the Muslim victors captured craftsmen who knew a secret of the Chinese. (Of course, not for the last time; it became a pattern.)
This secret had to do with boiling rags and pressing the ground pulp into sheets that dried stiff and smooth. Paper.
Shortly after the Abbasid capital moved farther east, some paper craftsmen came to Baghdad from the now-Muslim Turkestan region. It didn’t take long for the city’s industrial shops to realize its potential, since the grand translation project was beginning to ramp up already in the early Abbasid years. By the time Harun al-Rashid and his son Al-Mamoun were ordering mass translations, the paper industry was well-established.
Without paper, it would have been very difficult to keep up with their demands. Writing surfaces had been of three types until now: clay tablets, papyrus sheets, and parchment. Parchment was the most satisfactory: it was smooth and stiff, but it turned easily. It didn’t grow brittle within a short time like papyrus. It could be rubbed out or even whited over to re-use.
But making parchment was a messy process. It was a side industry to butchering, competing with tanning to process the skins. Like tanners, parchment makers had to soak, stretch, and scrape skins, throwing away most of the substance until all that was left was the integument itself and not much more. Parchment could be scraped too thin and suddenly break through in holes. It couldn’t be mass produced, since every piece had to be worked by hand.
Paper, on the other hand, needed drying time and only minimal (compared to parchment) hand processing. A Baghdad or Kufa merchant could spend a few years investing in wool felt, wooden frames, and wire screens, and at the end of it, he could turn out large amounts of paper with minimal human labor. Paper was as durable as parchment and soon became as popular or more popular for books. It certainly fed the House of Wisdom’s massive library expansion.
Paper remained an Eastern technology for a long time. It entered Europe via Spain, the other outpost of the Muslim empire. The town of Jativa in Valencia became a paper-making center some time between 800 and 1200. Eventually, the Reconquista brought Valencia back into Christian control. After 1260, paper-making spread to Italy and into the north.
Paper was quickly adopted by universities in Europe; book copyists made a decent living in those areas by copying the most in-demand portions of Aristotle and so on into informal books with wide margins for taking notes. Fine art books adopted paper more slowly, but the financial hub of Italy saw another advantage in it. Paper could be erased, but not as easily as parchment. Especially after the digit number system was adopted around the same time (13th and 14th centuries), paper financial records kept people honest. Official documents resisted the change, seeing paper as the cheapo, ephemeral alternative. Perhaps that’s why we still expect official documents like diplomas to be written on heavy paper, which we elevate by the name of “parchment.”