Chinese, Korean, Siamese, and Japanese stoneware decorated with glazes the colour range of which includes greens of various shades, olive, blue, and gray. The colours are the result of a wash of slip (liquefied clay) containing a high proportion of iron that is applied to the body before glazing. The iron interacts with the glaze during the firing and colours it. Celadons were prized in Eastern cultures long before their comparatively late introduction to the West. A wide demand led to their export to India, Persia, and Egypt in the Tang dynasty (618–907) and to most of Asia in the Song (960–1279) and Ming (1368–1644) dynasties. The ware was popular because of its beauty, because of a superstition that a celadon dish would break or change colour if poisoned food were put into it, and because, to the Chinese, it resembled jade. Yue ware, first made in the Han dynasty (206 BC–AD 220), is the earliest celadon.