In Korea, porcelains covered with a nearly translucent glaze and fired at high temperatures of approximately 1300 degrees Celsius, were first made in the 15th century. Underglaze iron oxide was used for creating designs on celadons during the Koryo dynasty (918-1392), but became especially popular in the 17th century. Underglaze copper-red decoration was first developed in the 12th century, but was virtually unused until the 18th century. Dating from the 18th century, this jar is painted in underglaze copper-red with large lotus plants. Gaps in the thickly applied glaze allow the red body color to show through in several places.