 Complete the following phrase:  China had been impressed with red-barbarian cannon since around 1600, when an enormous specimen was procured from some European ship. Paul Xua Jesuit convert who rose to very high office in large part due to the superiority of Western geometry, with its applications in astronomy, astrology, and accurate use of artillerywarmly encouraged the use of Portuguese guns to counter the ongoing Manchu invasions of northern China. However, during Corrêas time in China, there was debate among the mandarins as to whether the Manchus in the north or the increasing numbers and violence of European traders in the south were actually the greater threat. Shen Que, a Buddhist adept who rose to prominence in the Ministry of Rites, had succeeded in having the Jesuit mission in Nanjing expelled and its property confiscated in 1616 and Lu Zhaolong, a native of the Guangdong county on the mainland opposite Macao, published memorials heatedly arguing against permitting the South-Sea barbarians any access to China whatsoever. The competition of the factions was apparent when Xu succeeded in having a company of Portuguese gunners approved in 1620 only to have them returned the way theyd come in 1621, owing to local resistance upon various pretexts. After the fall of Guangning now Beizhen in Liaoning, Ignatius Suns extremely thorough memorials on the superiority of Western cannon and fortification attracted attention at the highest levels of the War Ministry. The Tianqi Emperor permitted a second Portuguese expedition to reach his capital in the spring of 1622. The same year, a 