We come now to an important class of blue and white ware which looms out large in many collections. I mean the big plates and jars with roughly executed designs often showing a Persian influence. The blue is never pure--indeed it is often little better than a slaty grey, and sometimes almost black. Most of what the dealers now know as ‘Ming porcelain’ may be included in this class. To understand the source of this porcelain we must refer the reader to what we shall have to say in Chapter XIII. about the trade of China with Persia in the time of Shah Abbas and with the north of India, during the reigns of the great Mogul rulers of the seventeenth century. The increasing demand from these countries coincided with a period of decline in China, for the period between the death of Wan-li in 1620 and the revival of the manufacture at King-te-chen towards the end of that century, is almost a blank in the history of Chinese porcelain. But the export trade that had sprung up at the end of the sixteenth century was actively carried on in spite of the political troubles, and at no other time was the nature of the ware produced so largely influenced by the foreign demand. But this demand was at first chiefly for the Mohammedan East, and what reached Europe was mostly the result of re-exportation from India and from the Persian Gulf.[98] This picturesque and decorative ware is well represented at South Kensington by specimens obtained in Persia, and many fine pieces have lately been brought from India. Of this class of blue and white ware we have already spoken in a former chapter (see p. 84). In Egypt, again, blue and white porcelain was greatly appreciated both for decorative purposes and for common use. Large plates and dishes painted with a scale-like pattern, formed of petals of flowers, are still to be found in the old Arab houses of Cairo. Already by the beginning of the seventeenth century plates and bowls of the Sinico-Persian type must have reached Holland in large quantities, and we find them frequently introduced into their pictures by the still-life painters of the time. I will only give two examples: (1) A large still-life at Dresden by Frans Snyders (1579-1657), where as many as eight plates and bowls, mostly roughly decorated with a greyish cobalt _sous couverte_, are introduced; (2) a small picture in the Louvre by William Kalff (1621-1693). Here we see a large ‘ginger-jar’ with deep blue ground and white reserves. The porcelain introduced by the Dutch painters is without exception of the blue and white class, and in the earlier works the slaty blue tints are the most common.