宣徳帝
In 1421, Yongle moved the "Jingshi" of the Ming to Beijing, which made Beijing the main capital of the Ming dynasty. From Beijing, Yongle launched multiple campaigns against the Mongols. After he died in 1424, his son, the Hongxi Emperor, ordered the capital be moved back to Nanjing, but died of illness in 1425. The Hongxi Emperor sent his son, the future Xuande Emperor, to Nanjing to prepare for the move, but the latter chose to keep the capital in Beijing after his accession to the throne. Like his grandfather, the Xuande Emperor was interested in monitoring affairs on the northern frontier. Most of the Great Wall in northern Beijing Municipality were built during the Ming dynasty.