The art and craft of carpet weaving has gone through periods of decline during times of political unrest, or under the influence of commercial demands. It particularly suffered from the introduction of synthetic dyes during the second half of the nineteenth century. Carpet weaving still plays a major part in the economy of modern Iran. Modern production is characterized by the revival of traditional dyeing with natural dyes, the reintroduction of traditional tribal patterns, but also by the invention of modern and innovative designs, woven in the centuries-old technique. Hand-woven Persian carpets and rugs were regarded as objects of high artistic and utilitarian value and prestige from the first time they were mentioned by ancient Greek writers, until today.