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 Shi Huang
In 246 BC, when King Zhuangxiang died after a short reign of just three years, he was succeeded on the throne by his 13-year-old son. At the time, Zhao Zheng was still young, so Lü Buwei acted as the regent prime minister of the State of Qin, which was still waging war against the other six states. Nine years later, in 235 BC, Zhao Zheng assumed full power after Lü Buwei was banished for his involvement in a scandal with Queen Dowager Zhao.