 A looted tomb with fine paintings is the Empress Dowager Wenming tomb of the 5th century CE, and the many tombs of the 7th-century Tang dynasty Qianling Mausoleum group are an early example of a generally well-preserved ensemble.The complex of Goguryeo Tombs, from a kingdom of the 5th to 7th centuries which included modern Korea, are especially rich in paintings.Only one of the Imperial Tombs of the Ming and Qing Dynasties has been excavated, in 1956, with such disastrous results for the conservation of the thousands of objects found, that subsequently the policy is to leave them undisturbed.