and gave his enfeoffed sons more military authority, especially those in the north, like the Prince of Yan. Adulthood and military career Zheng He's appearance as an adult was recorded: he was seven chi tall, had a waist that was five chi in circumference, cheeks and a forehead that was high, a small nose, glaring eyes, teeth that were white and well-shaped as shells, and a voice that was as loud as a bell. It is also recorded that he had great knowledge about warfare and was well-accustomed to battle. The young eunuch eventually became a trusted adviser to the prince and assisted him when the Jianwen Emperor's hostility to his uncle's feudal bases prompted the 13991402 Jingnan Campaign, which ended with the emperor's apparent death and the ascension of Zhu Di, Prince of Yan, as the Yongle Emperor. In 1393, the Crown Prince had died, thus the deceased prince's son became the new heir apparent. By the time the emperor died (24 June 1398), the Prince of Qin and the Prince of Jin had perished, which left Zhu Di, the Prince of Yan, as the eldest surviving son of the emperor. However, Zhu Di's nephew succeeded the imperial throne as the Jianwen Emperor. In 1398, he issued a policy known as xuēfān (), or "reducing the feudatories", which entails eliminating all princes by stripping their power and military forces. In August 1399, Zhu Di openly rebelled against his nephew. In 1399, Ma He successfully defended Beiping's city reservoir Zhenglunba against the imperial armies. In January 1402, Zhu Di began with his military campaign to capture the imperial capital Nanjing. Zheng He would be one of his commanders during that campaign. In 1402, Zhu Di's armies defeated the imperial forces and marched into Nanjing on 13 July 1402. Zhu Di accepted the elevation to emperor four days later. After ascending the throne as the Yongle Emperor, Zhu Di promoted Ma He as the Grand Director (, tàijiān) of the Directorate of Palace Servants (). During the Chinese New Year on 11 February 1404, the Yongle Emperor conferred the surname "Zheng" to Ma He, because he had distinguished himself defending the city reservoir Zhenglunba against imperial forces in the Siege of Beiping of 1399. Another reason was that the eunuch commander also distinguished himself during the 1402 campaign to capture the capital, Nanjing. In the new administration, Zheng He served in