Li Si built the Qin empire — then helped the eunuch who destroyed it

Li Si was the architect of the Qin empire's administration — standardised script, weights, measures, the abolition of hereditary fiefs, the burning of dissenting books. He had served Qin Shi Huang for thirty-six years as chancellor and was, by any measure, one of the two or three most powerful officials in Chinese history. When the First Emperor died suddenly at Shaqiu in 210 BCE, the succession was Li Si's to manage.

The emperor's will named his eldest son Fusu. But Fusu was close to the general Meng Tian, whose appointment would have displaced Li Si. The chief eunuch Zhao Gao, who tutored the younger son Hu Hai, proposed forging the will. Li Si — the man who had spent his career calculating advantage — agreed. The forged edict ordered Fusu to take his own life and installed Hu Hai as Qin Er Shi.

Within months Zhao Gao isolated the new emperor from every minister except himself. Li Si submitted a memorial comparing Zhao Gao to historical usurpers: 'He has the wealth of a private house equal to the public treasury, and the ambition of a traitor.' The emperor showed the memorial to Zhao Gao. Li Si was arrested, tortured until he confessed to treason, and executed at the market of Xianyang in 208 BCE — by the Five Punishments, a method Li Si himself had codified into law. His family to the third degree was exterminated. Two years later the Qin dynasty collapsed.

Before his death Li Si turned to his middle son and said: 'I wish that you and I could take our yellow dog and go out through the eastern gate of Shang Cai to chase the crafty hare. But how could we do that!' The dynasty he built lasted fifteen years. The man he empowered outlived him by two.