Emperor Cheng, (Zhu Di) an uncle of the previous emperor Huidi, took power in a veritable coup d'etat. He installed the capital in Beijing, which he had reconstructed. He became the chief architect of the northern border defense. In addition to being an excellent tactician he ruled as a dynamic leader who managed to reestablish order in the affairs of state. History considers his reign (the Yongle era) as brilliant. Later known as Chengzu, considered a son of Korean concubine of Taizu, did his best to weaken the power of the imperial princes. The new emperor transferred the principal capital to Beijing (northern capital), which until then had been known as Beiping (northern Peace). He restored the Grand Canal from the Yangzi to the Yellow River. This helped to improve the transport of grains to the north.

At Beijing, the emperor had the palace formally occupied by the Yuan completely resurrected. This project lasted for 14 years and involved the labor of several hundred thousand workers. Also he started the construction of his tomb north of Beijing. His reign began an intensification of diplomatic and commercial activity on the seas. At the beginning of the 15th century the Chinese navy remained ahead of that of the Portuguese and Spanish. Seven expeditions by Zheng He had traveled to Java, Sumatra, Ceylon, India, the Persian Gulf, and the coast of eastern Africa.