Chinese carpets are known to have been produced nearly 2,000 years ago. The patterns on older rugs were influenced by ceramic painters; they may display dragon, Buddhist, and other religious motifs. Cotton was used for the foundation of early carpets along with big knots to achieve thick but flexible rugs. Originally, rugs were produced for used within the country only, but by the early 19th century, rugs were being exported. Contact with the west radically altered production methods.