In the second half of the nineteenth century the Qing dynasty entered into a critical period. The Xianfeng emperor, never a healthy man at the best of times, died on February 11 1861. He was succeeded by his five-year old son Caiqun as the Tongzhi emperor (1862-1874). Caiqun was a minor for most of his reign and affairs of state were in the hands of a Council of Regents. A palace coup brought to power Prince Gong, the younger bother of the Xianfeng emperor and Xianfeng's two empresses, Ci Xi and Ci An, who ruled as regents. Ci Xi, the Empress Dowager gradually became the dominant regent and then the de facto ruler of China, a fact that conservative Manchu and Chinese officials found it extremely difficult to accept.