As China had been under the conquest of Mongol Empire, all Chinese vassal state subsequently controlled by the Mongol emperors of China. Early in 1292, Kublai Khan is said to have sending an expedition to northern Borneo, before departing for the invasion of Java in 1293. As a result of this campaign, it is believed that many of his followers in addition to other Chinese traders eventually settled and established their own colony at Kinabatangan River. In the 14th century, Brunei became the vassal state of Majapahit but in 1370 transferred its allegiance to Ming dynasty of China. The Maharaja Karna of Borneo then paid a visit to Nanjing with his family until his death. He was succeeded by his son Hsia-wang who agreed to send tribute to China once every three years. Since then, Chinese junks came to northern Borneo with cargoes of spices, bird nests, shark fins, camphor, rattan and pearls. More Chinese traders eventually settled in Kinabatangan, as stated in both Brunei and Sulu records. A younger sister of Ong Sum Ping (Huang Senping), the Governor of the Chinese settlement then married Sultan Ahmad of Brunei. Perhaps due to this relationship, a burial place with 2,000 wooden coffins, some estimated to be 1,000 years old, were discovered in Agop Batu Tulug Caves in the Kinabatangan area. It is believed that this type of funeral culture was brought by traders from Mainland China and Indochina to northern Borneo as similar wooden coffins were also discovered in these countries. In addition with the discovery of Chinese ceramics from a shipwreck in Tanjung Simpang Mengayau which estimated to be from 960 to 1127 A.D. of Song dynasty and Vietnamese Đông Sơn drum in Bukit Timbang Dayang on Banggi Island that had existed between 2,000 and 2,500 years ago.