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).
King Zhaoxiang of Qin
In 273 BC, Wei and Zhao allied together to attack Han's Huayang (華陽). Qin offered military help to Han, defeating and killing 130,000 Wei soldiers, and drowning 20,000 Zhao soldiers in the Yellow River. In 269 BC, King Huiwen of Zhao backflipped on his previous promise to send hostages and concede land. In response, Qin attacked Zhao and laid siege to Yuyu (閼與). The siege was lifted after the Zhao general Zhao She (趙奢) ambushed and decisively defeated the invading Qin army. In 265 BC, Qin struck back at Zhao and captured three cities, and King Huiwen of Zhao resorted to sending his son to the state of Qi in exchange for Qi assistance, which forced the Qin army to withdraw.