However, Mao Zedong argued that China would have developed into a Capitalist society even without foreign imperialist influence. Mao claimed that bourgeois and proletarian classes did not exist before the imperialist powers started to affect China after the Opium war. Mao thought that for China, imperialism was even worse a threat than the bourgeois class. complained that Shang Yue's theory glorified opium trade as a progressive force, and degraded Qing government and its subjects for active resistance. Shang was forced to admit in early 1958 that he had produced revisionist historiography, and was purged later that year. Jungmin Seo argues that reactions to Shang's theory show Chinese historians' fear that greater emphasis on internal proto-capitalism might divert too much attention from foreign capitalism's influence that transformed China into a semi-colonial or semi-feudal status.