Geng Zhongming Geng Zhongming ( ) ( 1604 – 1649 ) was a military leader who lived through the transition from the Ming ( 1368 – 1644 ) to the Qing ( 1644 – 1912 ) dynasty , during which he served both sides . His grandson Geng Jingzhong ( 耿精忠 ; d . 1682 ) was one of the Three Feudatories who rebelled against Qing rule in the 1670s . Under Ming service . Geng Zhongming had first served under Ming warlord Mao Wenlong near the border of Joseon Korea . When the latter was executed by Yuan Chonghuan in 1629 for insubordination , Geng and other military leaders like Kong Youde ( 孔有德 ; 1602 – 1654 ) refused to serve Yuan . With their troops , they fled by boat from the Liaodong peninsula to Dengzhou ( 登州 ) in Shandong . There , Geng was hired by Shandong governor Sun Yuanhua ( 孫元化 ) and allowed to join the Dengzhou garrison , where Sun was casting European - style cannon with the help of Portuguese soldiers . Sun gave Geng and Kong some training in the use of Portuguese artillery . In February 1632 , Kong and Geng rebelled , established a separatist regime in Dengzhou ( Kong was named " king " ) , and tried to seize other towns in eastern Shandong , but they were eventually dislodged by a Ming relief force . In May 1633 they crossed the Bohai Gulf back to Liaodong and submitted to Hong Taiji ( 1592 – 1643 ) , khan of the Jurchens and soon - to - be emperor of the Qing dynasty . Under Qing service . Like Kong , Geng was allowed to retain control of his own troops ( about 6 , 000 of them ) . In 1633 he helped Manchus capture the town of Lüshun , and in 1634 he accompanied a raiding expedition near Datong in Shanxi . In 1636 he was given the title of Prince Huaishun ( 懷順王 ) . He also led his troops into battle during the Qing ' s second invasion of Korea . In 1642 his soldiers were incorporated into the Chinese Plain Yellow Banner . In April 1644 , bandit leader Li Zicheng seized the Ming imperial capital Beijing and prodded the Chongzhen Emperor ( r . 1627 – 1644 ) to commit suicide . Under the leadership of prince - regent Dorgon , the Qing pretexted to take revenge on Li to attack China . In late May 1644 Dorgon and his new ally Ming general Wu Sangui defeated Li at the Battle of Shanhai Pass and soon took Beijing from the hands of the rebel . Geng Zhongming was sent to accompany Prince Dodo in pursuit of Li , who was retreating to his former headquarters in Xi ' an ( Shanxi ) . After Li had been defeated , Geng took part in the Qing conquest of Jiangnan , then fought the troops of the Prince of Gui of the Southern Ming ( 1644 – 1662 ) , a loyalist movement that was trying to reestablish the fallen Ming dynasty . When he returned to the capital in 1648 , his nobility title was changed to " Prince who Pacifies the South " ( 靜南王 " Jingnan wang " ) . Put in sole charge of a campaign to attack Guangdong , Geng had reached Jiangxi when he heard that he was being accused of protecting a subordinate who had harbored runaway slaves . He found three hundred slaves in his camp , sent them back to the capital in chains , and , without waiting for a verdict , committed suicide on 30 December 1649 in Ji ' an , Jiangxi . His troops , now led by his son Geng Jimao ( 耿繼茂 ; d . 1671 ) , continued to fight the Southern Ming .