A carpet is any loom-woven, felte textile or grass floor covering. The term was also used for table and wall coverings, as carpets were not commonly used on the floor in European interiors until the 18th century. The hand-knotted pile carpet probably originated in Central Asia between the 3rd and 2nd millennium BC. Carpet-making was introduced to Spain in 10th century by the Moors. The Crusades brought Turkish carpets to all of Europe, where they were primarily hung on walls or used on tables. Only with the opening of trade routes in the 17th century were significant numbers of Persian rugs introduced to Western Europe.