Unified Silla regularly engaged in trade with China’s Tang Dynasty, and the two nations mutually influenced one another’s culture. Thus, many ceramics and gold metalcrafts produced by Tang have been found in areas around Gyeongju, formerly the site of the Silla capital. One type of artifact that demonstrates this cultural exchange was Tang three-colored pottery, the influence of which can be seen in Silla green glazed pottery, made with similar techniques. The green glaze contains lead, which turns a greenish color when fired at relatively low temperatures. Green glazed pottery first appeared in Silla around the seventh century, and it was primarily used as a cinerary urn.