Question: How long had the city containing some of the finest and oldest museums in China been the capitol city of Yaxing Coach's headquarters location?

Knowledge 1: Nanjing
Nanjing has some of the oldest and finest museums in China. Nanjing Museum, formerly known as National Central Museum during ROC period, is the first modern museum and remains as one of the leading museums in China having 400,000 items in its permanent collection,. The museum is notable for enormous collections of Ming and Qing imperial porcelain, which is among the largest in the world. Other museums include the City Museum of Nanjing in the Chaotian Palace, the Oriental Metropolitan Museum, the China Modern History Museum in the Presidential Palace, the Nanjing Massacre Memorial Hall, the Taiping Kingdom History Museum, Jiangning Imperial Silk Manufacturing Museum, Nanjing Yunjin Museum, Nanjing City Wall Cultural Museum, Nanjing Customs Museum in Ganxi House, Nanjing Astronomical History Museum, Nanjing Paleontological Museum, Nanjing Geological Museum, Nanjing Riverstones Museum, and other museums and memorials such Zheng He Memorial, Jinling Four Modern Calligraphers Memorial. [SEP] Knowledge 2: Nanjing
Archaeological discovery shows that "Nanjing Man" lived in more than 500 thousand years ago. Zun, a kind of wine vessel, was found to exist in Beiyinyangying culture of Nanjing in about 5000 years ago. In the late period of Shang dynasty, Taibo of Zhou came to Jiangnan and established Wu state, and the first stop is in Nanjing area according to some historians based on discoveries in Taowu and Hushu culture. According to legend,[which?] Fuchai, King of the State of Wu, founded a fort named Yecheng (冶城) in today's Nanjing area in 495 BC. Later in 473 BC, the State of Yue conquered Wu and constructed the fort of Yuecheng (越城) on the outskirts of the present-day Zhonghua Gate. In 333 BC, after eliminating the State of Yue, the State of Chu built Jinling Yi (金陵邑) in the western part of present-day Nanjing. It was renamed Moling (秣陵) during reign of Qin Shi Huang. Since then, the city experienced destruction and renewal many times.[citation needed] The area was successively part of Kuaiji, Zhang and Danyang prefectures in Qin and Han dynasty, and part of Yangzhou region which was established as the nation's 13 supervisory and administrative regions in the 5th year of Yuanfeng in Han dynasty (106 BC). Nanjing was later the capital city of Danyang Prefecture, and had been the capital city of Yangzhou for about 400 years from late Han to early Tang. [SEP] Knowledge 3: Yaxing Coach
Yaxing Coach (Yangzhou Yaxing Motor Coach Co., Ltd) is a bus manufacturer based in Yangzhou, Jiangsu, China. It is a subsidiary of Jiangsu Yaxing that was founded in 1998. Buses are produced under the "Yaxing", "Yangtse（Yangzlv）", and more recently Asiastar brands.
Knowledge 1: Yaxing Coach
Yaxing Coach (Yangzhou Yaxing Motor Coach Co., Ltd) is a bus manufacturer based in Yangzhou, Jiangsu, China. It is a subsidiary of Jiangsu Yaxing that was founded in 1998. Buses are produced under the "Yaxing", "Yangtse（Yangzlv）", and more recently Asiastar brands. [SEP] Knowledge 2: Nanjing
Nanjing has some of the oldest and finest museums in China. Nanjing Museum, formerly known as National Central Museum during ROC period, is the first modern museum and remains as one of the leading museums in China having 400,000 items in its permanent collection,. The museum is notable for enormous collections of Ming and Qing imperial porcelain, which is among the largest in the world. Other museums include the City Museum of Nanjing in the Chaotian Palace, the Oriental Metropolitan Museum, the China Modern History Museum in the Presidential Palace, the Nanjing Massacre Memorial Hall, the Taiping Kingdom History Museum, Jiangning Imperial Silk Manufacturing Museum, Nanjing Yunjin Museum, Nanjing City Wall Cultural Museum, Nanjing Customs Museum in Ganxi House, Nanjing Astronomical History Museum, Nanjing Paleontological Museum, Nanjing Geological Museum, Nanjing Riverstones Museum, and other museums and memorials such Zheng He Memorial, Jinling Four Modern Calligraphers Memorial. [SEP] Knowledge 3: Nanjing
Archaeological discovery shows that "Nanjing Man" lived in more than 500 thousand years ago. Zun, a kind of wine vessel, was found to exist in Beiyinyangying culture of Nanjing in about 5000 years ago. In the late period of Shang dynasty, Taibo of Zhou came to Jiangnan and established Wu state, and the first stop is in Nanjing area according to some historians based on discoveries in Taowu and Hushu culture. According to legend,[which?] Fuchai, King of the State of Wu, founded a fort named Yecheng (冶城) in today's Nanjing area in 495 BC. Later in 473 BC, the State of Yue conquered Wu and constructed the fort of Yuecheng (越城) on the outskirts of the present-day Zhonghua Gate. In 333 BC, after eliminating the State of Yue, the State of Chu built Jinling Yi (金陵邑) in the western part of present-day Nanjing. It was renamed Moling (秣陵) during reign of Qin Shi Huang. Since then, the city experienced destruction and renewal many times.[citation needed] The area was successively part of Kuaiji, Zhang and Danyang prefectures in Qin and Han dynasty, and part of Yangzhou region which was established as the nation's 13 supervisory and administrative regions in the 5th year of Yuanfeng in Han dynasty (106 BC). Nanjing was later the capital city of Danyang Prefecture, and had been the capital city of Yangzhou for about 400 years from late Han to early Tang.
Knowledge 1: Yaxing Coach
Yaxing Coach (Yangzhou Yaxing Motor Coach Co., Ltd) is a bus manufacturer based in Yangzhou, Jiangsu, China. It is a subsidiary of Jiangsu Yaxing that was founded in 1998. Buses are produced under the "Yaxing", "Yangtse（Yangzlv）", and more recently Asiastar brands. [SEP] Knowledge 2: Nanjing
Nanjing has some of the oldest and finest museums in China. Nanjing Museum, formerly known as National Central Museum during ROC period, is the first modern museum and remains as one of the leading museums in China having 400,000 items in its permanent collection,. The museum is notable for enormous collections of Ming and Qing imperial porcelain, which is among the largest in the world. Other museums include the City Museum of Nanjing in the Chaotian Palace, the Oriental Metropolitan Museum, the China Modern History Museum in the Presidential Palace, the Nanjing Massacre Memorial Hall, the Taiping Kingdom History Museum, Jiangning Imperial Silk Manufacturing Museum, Nanjing Yunjin Museum, Nanjing City Wall Cultural Museum, Nanjing Customs Museum in Ganxi House, Nanjing Astronomical History Museum, Nanjing Paleontological Museum, Nanjing Geological Museum, Nanjing Riverstones Museum, and other museums and memorials such Zheng He Memorial, Jinling Four Modern Calligraphers Memorial. [SEP] Knowledge 3: Zhejiang
The Song dynasty reëstablished unity around 960. Under the Song, the prosperity of South China began to overtake that of North China. After the north was lost to the Jurchen Jin dynasty in 1127 following the Jingkang Incident, Hangzhou became the capital of the Southern Song under the name Lin'an. Renowned for its prosperity and beauty, it may have been the largest city in the world at the time. From then on, north Zhejiang and neighboring south Jiangsu have been synonymous with luxury and opulence in Chinese culture. The Mongol conquest and the establishment of the Yuan dynasty in 1279 ended Hangzhou's political clout, but its economy continued to prosper. Marco Polo visited the city, which he called "Kinsay" (after the Chinese Jingshi, meaning "Capital City") claiming it was "the finest and noblest city in the world".

Answer: about 400 years