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 Xuan
Queen Dowager Xuan (; 338–265 BC), also called Mi Bazi (), was a girl from the royal family of the Kingdom of Chu and one of the imperial concubines (consorts but not the wife) of King Huiwen of Qin. She gave birth to King Zhaoxiang of Qin (r. 306–251 BC) and acted as his regent when he was young. As queen dowager, she entered illicit relations with the "barbarian" Yiqu king and had two sons with him, but later tricked and killed him. Following that coup, the Qin army marched into Yiqu territory at the queen dowager's orders; the Qin annihilated Yiqu and thus came to possess the Ordos region.