The Hongwu Emperor was succeeded by his young grandson the Jianwen Emperor. His attempts to rein in the fiefs of his powerful uncles provoked the Jingnan Rebellion and ultimately his usurpation by his uncle, the Prince of Yan. Yan's powerbase lay in Shuntian and he quickly resolved to move his capital north from Yingtian (Nanjing) to the ruins at Beiping. He shortened the northern boundaries of the city and added a new and separately walled southern district. Upon the southern extension of the Taiye Lake (the present Nanhai), the raising of Wansui Hill over Yuan ruins, and the completion of the Forbidden City to its south, he declared the city his northern capital Beijing. With one brief interruption, it has borne the name ever since.