18.1 Paper is made of cellulose fibers Paper was first made HARDWOOD FIBE in China as early as AD 100, of mulberry bark. and then introduced to Western SOFTWOOD FIBERS world by Arabs in eighth century. The first paper mills were built in Spain in 11th century18.1 Paper is made of cellulose fibers • Paper was first made in China as early as AD 100, of mulberry bark, and then introduced to Western world by Arabs in eighth century. The first paper mills were built in Spain in 11th century