What is the earliest place name in Lanzhou?

Today's Lanzhou was once called Jincheng in history. There are generally two views on the origin of Jincheng. One is "building a city to dig gold", so there is the saying of Jincheng; It also comes from the meaning that the terrain is dangerous and impregnable. Nowadays, there is no tension in the north and south mountains of Lanzhou, and the Jincheng County built in the Han Dynasty has long since disappeared into the luxury of the city. There is only one unchanging story in my memory. Today, some scholars start with this folklore and gradually describe to us the scene when Emperor Wu of the Han Dynasty established Jincheng County. There is no doubt that the earliest recorded urban construction in Lanzhou history began in Jincheng County established by Emperor Wu of Han Dynasty. This is the former life of Lanzhou-during the Western Han Dynasty, the Huns and Qiang people often harassed, and by the time of Emperor Wu of the Han Dynasty, the national strength was strong. In order to cut off the connection between Xiongnu and Qiang people, Emperor Wu of the Han Dynasty ordered Huo Qubing, an ancient general, to cross the Yellow River twice in the spring and summer of the second year of Yuanshou, to attack Xiongnu, defeated Xiongnu in Hexi Corridor and built four counties in Hexi successively. The Han Dynasty controlled Hexi. This year, Huo Qubing sent Li Xi, a big bank, to build a castle near Xigu City on the south bank of the Yellow River and set up Jincheng County. Later, the Han Dynasty governed the Huangshui River basin and established the Han County. With the increase of Han county, Jincheng County was established in the sixth year of Zhao Di in the Western Han Dynasty (8 1 year BC), and the county ruled Wu Yun (now Minhe Ancient Repair in Qinghai). This may be the "embryonic form" of Lanzhou today. If Lanzhou in the Han Dynasty was still a residential area dominated by ethnic minorities, then the northwest immigrants in the Ming Dynasty completely turned Lanzhou into an immigrant city.