Answer
Guangxu's reign was a contravention of Qing's dynastic custom. The Qing emperors were usually succeeded by their eldest sons, but Guangxu's father, the Xianfeng Emperor, died without a son. The Empress Dowager Ci'an and Empress Dowager Cixi decided to pass over Guangxu's older half-brother and choose Guangxu as emperor instead. This was a violation of Qing dynastic custom, which stipulated that the eldest son should succeed to the throne.