Hong Taiji renamed his father's state and created the Qing dynasty
Nurhaci's eighth son inherited a Manchu kingdom called the Later Jin in 1626. Within a decade Hong Taiji had brought Han Chinese into government, conquered Inner Mongolia, forced Korea to break with the Ming, and renamed his realm the Qing, the dynasty that would go on to rule China.
Hong Taiji lived from 1592 to 1643. Even his name is uncertain: hong taiji was a Manchu borrowing of a Mongolian title, itself derived from the Chinese word for crown prince, and it may have been a title rather than a personal name. Because Manchu records avoided emperors' personal names, documents often call him simply the Fourth Beile, the fourth-ranked of Nurhaci's eight senior princes. Western writers long called him Abahai, a name now considered a mistake. He is worshipped under the temple name Taizong, customary for a dynasty's second emperor.
His route to power involved hard manoeuvring. Gossip long held that he helped push Lady Abahai, mother of his half-brother Dorgon, to suicide to block a rival succession. Afterwards he swapped his White Banners for the Yellow Banners Dorgon and Dodo had inherited, taking control of the two strongest units of the Eight Banners, the military and civil system he went on to develop.
He reshaped the state around its diversity. Nurhaci had distrusted his Han followers after a 1623 revolt; Hong Taiji recruited Han officials and in 1632, with Prince Yoto, arranged a mass wedding of about 1,000 Han officers and officials to Manchu women. After conquering the Mongols he set up a Mongol office in 1636, renamed the Lifanyuan in 1638, to govern Inner Mongolia indirectly. He publicly sponsored Tibetan Buddhism while privately fearing it eroded Mongol identity.
Militarily he was widely admired. In February 1627 his troops crossed the frozen Yalu River into Korea. In 1628 the Ming general Yuan Chonghuan beat him back with artillery, so Hong Taiji acquired powerful red cannons of his own to add to Asia's strongest cavalry. When Joseon Korea refused to recognise him as emperor, he invaded in 1636, and its surrender in 1637 forced it to cut ties with the Ming.
Source: Hong Taiji
