In 1836, a young man named Hong Xiuquan failed the imperial civil service examination and walked home carrying a packet of Christian pamphlets a missionary had handed him on the street. Two years later he suffered a complete mental breakdown — forty days of fever and visions. When he finally read those pamphlets six years after receiving them, he understood with complete and terrible clarity what the visions had meant.

He was the younger brother of Jesus Christ. The second son of God. Sent to China to destroy demons, overthrow the Qing dynasty, and establish the Heavenly Kingdom of Great Peace on earth.

What followed was the bloodiest civil war in human history. The Taiping Rebellion lasted fourteen years. Estimates of the death toll range from twenty million to fifty million people. More people may have died in this conflict than in  ...