This Tang dynasty (618–907) three-footed offering plate or dish is decorated with sancai (three-colour) lead glazes. The term actually refers to a palette that could include more than three colours, and in this example cobalt oxide blue glaze, a mineral pigment introduced into Chinese ceramics at this time, has been added to the standard three colours of brown, cream and green. Cobalt would later be used in blue-and-white underglaze decoration, beginning in the Yuan dynasty. The cobalt blue was probably imported from sources in Iran, reflecting the cosmopolitanism of Tang-period China.