Question: How long had the city considered to be a place that is popular with tourists been the capital city of the location of the Yaxing Coach headquarters?

Knowledge 1: Nanjing
Instead, Nanjing, as a popular tourist destination, hosts a series of government-organised events throughout the year. The annual International Plum Blossom Festival held in Plum Blossom Hill, the largest plum collection in China, attracts thousands of tourists both domestically and internationally. Other events include Nanjing Baima Peach Blossom and Kite Festival, Jiangxin Zhou Fruit Festival and Linggu Temple Sweet Osmanthus Festival. [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
Instead, Nanjing, as a popular tourist destination, hosts a series of government-organised events throughout the year. The annual International Plum Blossom Festival held in Plum Blossom Hill, the largest plum collection in China, attracts thousands of tourists both domestically and internationally. Other events include Nanjing Baima Peach Blossom and Kite Festival, Jiangxin Zhou Fruit Festival and Linggu Temple Sweet Osmanthus Festival. [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
Instead, Nanjing, as a popular tourist destination, hosts a series of government-organised events throughout the year. The annual International Plum Blossom Festival held in Plum Blossom Hill, the largest plum collection in China, attracts thousands of tourists both domestically and internationally. Other events include Nanjing Baima Peach Blossom and Kite Festival, Jiangxin Zhou Fruit Festival and Linggu Temple Sweet Osmanthus Festival. [SEP] Knowledge 3: Gavin & Stacey
Although the programme is set in Billericay, Essex, and Barry, Vale of Glamorgan, the three series were shot largely in Cardiff (which acted as the city itself but also as parts of Billericay), and also in Barry itself and the surrounding area, including Dinas Powys, Sully and Penarth. The show's popularity has been credited with boosting the tourist trade to Barry and its popular seafront of Barry Island, through visitors wishing to visit the various filming locations. Gavin's house was set in Billericay but was actually filmed on location in Laburnam Way, Dinas Powys in Wales. The opening episode features location shooting in Leicester Square in London which was filmed in 2006.

Answer: about 400 years