King Zhaoxiang of Qin
Because King Zhaoxiang had not yet legally come of age (traditionally at the age of 20), his mother, who was now known as Queen Dowager Xuan, became the regent. She was supported by her brothers, Wei Ran and Mi Rong (羋戎), as well as two other sons, Prince Yi (公子悝) and Prince Fu (公子巿), the four of them collectively known as the "Four Nobles" (四貴).
Queen Dowager Zhao
The daughter of a prominent family of Zhao, she was a concubine of the merchant Lü Buwei, who gave her to his protegé, Prince Yiren of Qin. A year later, she gave birth to a son named Zheng; the historian Sima Qian, ill-disposed towards the first emperor, claimed that the pregnancy was especially long and that the child was actually Lü's. The couple were living at the time in Handan, the capital of Zhao, where Yiren was a hostage; when Qin laid siege to the city, Lü was able to bribe the prince's way out of town but Lady Zhao and her infant son were forced to hide among her family. Thanks to Lü's intervention and diplomacy, Prince Yiren subsequently ascended the Qin throne, becoming known to history by his posthumous name King Zhuangxiang.