What is the origin of the name of the Summer Palace?

In the 15th year of Qianlong (1750), Emperor Qianlong spent 4.48 million taels of silver to honor his mother, Empress Dowager Chongqing, and converted it into Qingyi Garden, forming a royal garden area 20 kilometers from Tsinghua campus to Xiangshan. In the tenth year of Xianfeng (1860), Qingyi Garden was burned by the British and French allied forces. In the 14th year of Guangxu (1888), it was rebuilt and renamed the Summer Palace as a summer amusement park. In the 14th year of Guangxu (1888), on the first day of February, an imperial edict was published: "yanshou temple, the great benefactor of Wanshou Mountain, was the place where Emperor Gao Zongchun served the Empress Xiao Xian three times, and its original name was Qingyi Garden, which was especially auspicious. It is suggested to change it to the Summer Palace, where everything should be treated with velvet for good or ill luck. On the occasion of the year of Daqing, we bowed our heads and led the ministers to express our wishes to you and paid a little respect. " The name Qingyi Garden has been used since the 16th year of Qianlong (175 1) and has been used for 137 years. The garden itself experienced a turning point from prosperity to decline in the Qing Dynasty, from the ancient feudal empire to a semi-colonial and semi-feudal society, and then entered another period in the modern history of China in the name of "Summer Palace".