Paper is usually made of cellulose fibres. It is made through water suspension and is formed on a wire screen. The first papermaking can be traced back to about 105 AD in China. By the 14th century, there were already paper mills in several parts of Europe. The invention of the printing press in 1490 caused the great increase in the demand for paper. At the beginning of 19th century, people began using wood and vegetable pulps for making paper, instead of rags as primary source of fibre. Despite wood becoming the major source of fibre for making paper, people still used rag fibres for paper of maximum strength, durability, and permanence.