To redress the technological and numerical disparity, Hong Taiji created his own artillery corps in 1634, the "ujen cooha" (Chinese: ) from his existing Han troops who cast their own cannons in the European design with the help of defector Chinese metallurgists. One of the defining events of Hong Taiji's reign was the official adoption of the name "Manchu" for the united Jurchen people in November 1635. In 1635, the Manchus' Mongol allies were fully incorporated into a separate Banner hierarchy under direct Manchu command. Hong Taiji conquered the territory north of Shanhai Pass by Ming dynasty and Ligdan Khan in Inner Mongolia. In April 1636, Mongol nobility of Inner Mongolia, Manchu nobility and the Han mandarin held the Kurultai in Shenyang, and recommended the khan of Later Jin to be the emperor of the Great Qing empire. One of the Yuan Dynasty's jade seal was also dedicated to the emperor (Bogd Setsen Khan) by the nobility. When he was presented with the imperial seal of the Yuan dynasty after the defeat of the last Khagan of the Mongols, Hong Taiji renamed his state from "Great Jin" to "Great Qing" and elevated his position from Khan to Emperor, suggesting imperial ambitions beyond unifying the Manchu territories. Hong Taiji then proceeded to invade Korea again in 1636.