The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them. That's about the same time sheepskin was replacing papyrus in the Roman world. You make paper by spreading out a slurry of organic fibers and draining off the water.
Paper is a kind of felt made of overlapping fibers.
At first the Chinese made paper from hemp. They'd already been wrapping themselves in felt clothing. In AD 105, one Ts'ai Lun used paper to replace bamboo blocks as a writing surface. He made it from fibers of bark, bamboo, and hemp. By AD 500, the Chinese had experimented with rattan and mulberry and had finally settled on bamboo paper.