Other sources of eunuchs according to Liu, was that boys were captured/given as gifts from conquered tribes, prisoners of war who were captured and sent to the Forbidden City, and criminals. This last source is contested by Roy Bates, a British historian specializing on the Forbidden City and its occupants. He claims that "castration by beating the testicles was a severe punishment, second only to death, but these criminals were not accepted for imperial employment. Do you think an emperor would engage the services of a criminal? And do you think an emperor would engage the services of a criminal who had had his testicles crushed by beating? Would he not likely to be somewhat bitter? And potentially dangerous?"
