The ruler of Zhao was angry but Zheng's mother hid. He was not able to kill her or her son. Zheng's mother had been the girlfriend of Lü Buwei, but Lü gave her to Yiren when he fell in love with her. Sima Qian was not certain that Zheng was the son of Zichu and not the son of Lü Buwei, but most people thought that he was the son of Zichu, ruler of Qin. When Zichu died, Zheng got to be the new ruler of Qin. Because he was still very young when this took place, his mother and Lü Buwei were the true rulers.