The body of Sancai ceramics was made of white clay, coated with a layer of glaze, and fired at a temperature of 800 degrees Celsius. Sancai is a type of lead-glazed pottery: lead oxide was the principal flux in the glaze, often mixed with quartz in the proportion of 3:1.^[1] The polychrome effect was obtained by using as coloring agents copper (which turns green), iron (which turns brownish yellow), and less often manganese and cobalt (which turns blue).Sancai follows the development of green-glazed pottery dating back to the Han period (25-220CE).Predecessors to the Sancai style can also be seen in some Northern Qi (550-577) ceramic works. Northern Qi tombs have revealed some beautiful artifacts, such as porcellaneous ware with splashed green designs, previously thought to have been developed under the Tang dynasty. Such a jar has been found in a Northern Qi tomb, which was closed in 576 CE, and is considered as a precursor of the Tang Sancai style of ceramics.