A Manchu, she became a concubine of the emperor Xianfeng (ruled 1851–61), giving birth to a son in 1856 who came to the throne in 1862 as the emperor Tongzhi. Cixi acted as Regent for twelve years and, after Tongzhi’s death, resumed her position after the elevation of the latter’s four-year-old cousin to the throne as the emperor Guangxu. She maintained her power through a combination of ruthlessness and corruption, until the last decade of the century, when the emperor attempted to reverse her conservative policies (Hundred Days Reform). Cixi responded by imprisoning Guangxu and encouraging the Boxer Rising. Forced by foreign military forces to flee the capital, she returned in 1902, conceding some reforms, but still tried to delay the establishment of a constitutional monarchy.