as the Jianwen Emperor. In direct violation of the dynastic instructions, the Prince of Yan attempted to mourn his father in Nanjing, bringing a large armed guard with him. The imperial army was able to block him at Huai'an and, given that three of his sons were serving as hostages in the capital, the prince withdrew in disgrace. The Jianwen Emperor's harsh campaign against his weaker uncles (dubbed , lit. "Weakening the Marcher Lords") made accommodation much more difficult, however: Zhu Di's full brother, Zhu Su, Prince of Zhou, was arrested and exiled to Yunnan; Zhu Gui, Prince of Dai was reduced to a commoner; Zhu Bai, Prince of Xiang committed suicide under duress; Zhu Fu, Prince of Qi and Zhu Pian, Prince of Min were demoted all within the later half of 1398 and the first half of 1399. Faced with certain hostility, Zhu Di pretended to fall ill and then "went mad" for a number of months before achieving his aim of freeing his sons from captivity to visit him in the north in June 1399. On 5 August, Zhu Di declared that the Jianwen Emperor had fallen victim to "evil counselors" () and that the Hongwu Emperor's dynastic instructions obliged him to rise in arms to remove them, a conflict known as the Jingnan campaign. In the first year, Zhu Di survived the initial assaults by superior forces under Geng Bingwen and Li Jinglong thanks to superior tactics and capable Mongol auxiliaries. He also issued numerous justifications for his rebellion, including questionable claims to have been the son of Empress Ma and bold-faced lies that his father had attempted to name him as the rightful heir, only to be thwarted by bureaucrats scheming to empower Zhu Biao's son. Whether because of this propaganda or for personal motives, Zhu Di began to receive a steady stream of turncoat eunuchs and generals who provided him with invaluable intelligence allowing a hit-and-run campaign against the imperial supply depots along the Grand Canal. By 1402, he knew enough to be able to avoid the main hosts of the imperial army while sacking Xuzhou, Suzhou, and Yangzhou. The betrayal of Chen Xuan gave him the imperial army's Yangtze River fleet; the betrayal of Li Jinglong and the prince's half-brother Zhu Hui, Prince of Gu opened the gates of Nanjing on 13 July. Amid the disorder, the imperial palace quickly caught fire: Zhu