Rag paper is a category of paper that is made from a pulp of discarded textiles, rope and other fibre products. Rag paper in its various forms was a widely-used paper for most of the past two millennia. Production spread along the Silk Road from its early 2nd-century origin in China to the Islamic world by the 8th century. It was introduced into Christian Europe by the 12th century, and western Europe came to dominate rag production up until the mid-19th century, when rag paper was displaced in favour of far more cost-efficient pulpwood acidic paper.