The reeds were split, flattened together and scraped until thin and pliable. True parchment was actually made from stretched and dried animal skins. Parchment was used especially for maps and documents because the skins were durable and weather-resistant. A very fine parchment called vellum was made from calf skin. Around 105 AD, long before anyone else discovered paper, the Chinese used vegetable fibers to make the very first paper from pulp.
True paper comes from pulp - which is the physical rearrangement of fibers.
This increased the strength and absorbency of the paper made this way. Papermaking skills remained a Chinese secret until the 8th century when the Chinese city of Samorkand was captured by the Arabs. Soon after, the Arabs established a paper mill in Bagdad. Much traveling occurred over the next few hundred years. During the Crusades, what skills were not taught or traded, were simply taken.