As soon as porcelain developed an international market during the Tang Dynasty, many peoples in the Middle East and North Africa attempted to copy the Chinese product, producing many beautiful varieties of "soft porcelain" (a technically inferior product) in the process. In the latter part of the sixteenth century western Europeans joined in the quest when the Italians made a serious, but unsuccessful, effort to copy the Chinese product. In the latter part of the seventeenth century, the Saint-Cloud factory near Paris began to manufacture a soft porcelain, and in Germany glass makers, attempting to capture the European porcelain market, added tin oxide to their wares, thus producing an opaque milk