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).
Qin's wars of unification
In 264 BC, Tian Jian became the king of Qi. However, as he was too young to rule, his mother the queen dowager became his regent. Qin bribed Hou Sheng (後勝), the chancellor of Qi, to dissuade King Jian from helping the other states while they were being attacked by Qin. By 221 BC, Qi was the only state in China yet to be conquered by Qin. Qi hurriedly mobilised its armies to its western borders as a safeguard against a possible Qin invasion, even though its military was not well equipped and morale was low.