His name is Zhu Di (朱棣), he became known as Chengzu of Ming Dynasty (明成祖 also written Cheng Zu, or Ch'eng Tsu (Cheng Tsu) in Wade-Giles)) after becoming emperor following a civil war. His era name was Yongle (also Yung-lo in Wade-Giles).
He moved the capital from Nanjing to Beijing. According to a popular legend, the capital was moved when the emperor's advisors brought the emperor to the hills surrounding Nanjing and pointed out the emperor's palace showing the vulnerablity of the palace to artillery attack.
See also: Hongwu Emperor of China