(r. 1505–21), who succeeded the Hongzhi Emperor, built a palace on the banks of the Western Lake and turned the area into an imperial garden. He renamed Jar Hill "Golden Hill" (金山) and named the lake "Golden Sea" (金海). Both the Zhengde Emperor and the Wanli Emperor (r. 1572–1620) enjoyed taking boat rides on the lake. During the reign of the Tianqi Emperor (r. 1620–27), the court eunuch Wei Zhongxian took the imperial garden as his personal property. Qing dynasty In the early Qing dynasty, Jar Hill served as the site for horse stables in the imperial palace. Eunuchs who committed offences were sent there to weed and cut grass. At the beginning of the reign of the Qianlong Emperor (r. 1735-1796), many imperial gardens were built in the area around present-day Beijing's Haidian District and accordingly, water consumption increased tremendously. At the time, much of the water stored in the Western Lake came from the freshwater spring on Jade Spring Hill, while a fraction came from the Wanquan River (萬泉河). Any disruption of the water flow from Jade Spring Hill would affect the capital's water transport and water supply systems. Around 1749, the Qianlong Emperor decided to build a palace in the vicinity of Jar Hill and the Western Lake to celebrate the 60th birthday of his mother, Empress Dowager Chongqing. In the name of improving the capital's waterworks system, he ordered the Western Lake to be expanded further west to create two more lakes, Gaoshui Lake (高水湖) and Yangshui Lake (養水湖). The three lakes served not only as a reservoir for the imperial gardens but also as a source of water for the surrounding agricultural areas. The Qianlong Emperor collectively named the three lakes "Kunming Lake" after the Kunming Pool (昆明池) constructed by Emperor Wu (r. 141–187 BCE) in the Han dynasty for the training of his navy. The earth excavated from the expansion of Kunming Lake was used to enlarge Jar Hill, which was renamed "Longevity Hill". The Summer Palace, whose construction was completed in 1764 at a cost of over 4.8 million silver taels, was first named "Qingyiyuan" (清漪園; 'Gardens of Clear Ripples"'). The design of the Summer Palace was based on a legend in Chinese mythology about three divine mountains in the East Sea, namely Penglai, Fangzhang (方丈) and Yingzhou (瀛洲). The three islands in Kunming Lake – Nanhu Island (南湖島), Tuancheng Island (團城島) and