Question: How long had the city where the Yongle emperor greeted the person to whom the edict was addressed been the capitol of Yaxing Coach's headquarters location?

Knowledge 1: Sino-Tibetan relations during the Ming dynasty
The Information Office of the State Council of the PRC preserves an edict of the Zhengtong Emperor (r. 1435–1449) addressed to the Karmapa in 1445, written after the latter's agent had brought holy relics to the Ming court. Zhengtong had the following message delivered to the Great Treasure Prince of Dharma, the Karmapa: [SEP] Knowledge 2: Sino-Tibetan relations during the Ming dynasty
During his travels beginning in 1403, Deshin Shekpa was induced by further exhortations by the Ming court to visit Nanjing by April 10, 1407. Norbu writes that the Yongle Emperor, following the tradition of Mongol emperors and their reverence for the Sakya lamas, showed an enormous amount of deference towards Deshin Shekpa. The Yongle Emperor came out of the palace in Nanjing to greet the Karmapa and did not require him to kowtow like a tributary vassal. According to Karma Thinley, the emperor gave the Karmapa the place of honor at his left, and on a higher throne than his own. Rossabi and others describe a similar arrangement made by Kublai Khan and the Sakya Phagpa lama, writing that Kublai would "sit on a lower platform than the Tibetan cleric" when receiving religious instructions from him. [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. [SEP] Knowledge 4: 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: Sino-Tibetan relations during the Ming dynasty
The Information Office of the State Council of the PRC preserves an edict of the Zhengtong Emperor (r. 1435–1449) addressed to the Karmapa in 1445, written after the latter's agent had brought holy relics to the Ming court. Zhengtong had the following message delivered to the Great Treasure Prince of Dharma, the Karmapa: [SEP] Knowledge 2: Sino-Tibetan relations during the Ming dynasty
During his travels beginning in 1403, Deshin Shekpa was induced by further exhortations by the Ming court to visit Nanjing by April 10, 1407. Norbu writes that the Yongle Emperor, following the tradition of Mongol emperors and their reverence for the Sakya lamas, showed an enormous amount of deference towards Deshin Shekpa. The Yongle Emperor came out of the palace in Nanjing to greet the Karmapa and did not require him to kowtow like a tributary vassal. According to Karma Thinley, the emperor gave the Karmapa the place of honor at his left, and on a higher throne than his own. Rossabi and others describe a similar arrangement made by Kublai Khan and the Sakya Phagpa lama, writing that Kublai would "sit on a lower platform than the Tibetan cleric" when receiving religious instructions from him. [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. [SEP] Knowledge 4: Nanjing
The first emperor of the Ming dynasty, Zhu Yuanzhang (the Hongwu Emperor), who overthrew the Yuan dynasty, renamed the city Yingtian, rebuilt it, and made it the dynastic capital in 1368. He constructed a 48 km (30 mi) long city wall around Yingtian, as well as a new Ming Palace complex, and government halls. It took 200,000 laborers 21 years to finish the project. The present-day City Wall of Nanjing was mainly built during that time and today it remains in good condition and has been well preserved. It is among the longest surviving city walls in China. The Jianwen Emperor ruled from 1398 to 1402.
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: Sino-Tibetan relations during the Ming dynasty
Throughout the following month, the Yongle Emperor and his court showered the Karmapa with presents. At Linggu Temple in Nanjing, he presided over the religious ceremonies for the Yongle Emperor's deceased parents, while twenty-two days of his stay were marked by religious miracles that were recorded in five languages on a gigantic scroll that bore the Emperor's seal. During his stay in Nanjing, Deshin Shekpa was bestowed the title "Great Treasure Prince of Dharma" by the Yongle Emperor. Elliot Sperling asserts that the Yongle Emperor, in bestowing Deshin Shekpa with the title of "King" and praising his mystical abilities and miracles, was trying to build an alliance with the Karmapa as the Mongols had with the Sakya lamas, but Deshin Shekpa rejected the Yongle Emperor's offer. In fact, this was the same title that Kublai Khan had offered the Sakya Phagpa lama, but Deshin Shekpa persuaded the Yongle Emperor to grant the title to religious leaders of other Tibetan Buddhist sects. [SEP] Knowledge 3: Sino-Tibetan relations during the Ming dynasty
The Information Office of the State Council of the PRC preserves an edict of the Zhengtong Emperor (r. 1435–1449) addressed to the Karmapa in 1445, written after the latter's agent had brought holy relics to the Ming court. Zhengtong had the following message delivered to the Great Treasure Prince of Dharma, the Karmapa: [SEP] Knowledge 4: Nanjing
The first emperor of the Ming dynasty, Zhu Yuanzhang (the Hongwu Emperor), who overthrew the Yuan dynasty, renamed the city Yingtian, rebuilt it, and made it the dynastic capital in 1368. He constructed a 48 km (30 mi) long city wall around Yingtian, as well as a new Ming Palace complex, and government halls. It took 200,000 laborers 21 years to finish the project. The present-day City Wall of Nanjing was mainly built during that time and today it remains in good condition and has been well preserved. It is among the longest surviving city walls in China. The Jianwen Emperor ruled from 1398 to 1402.

Answer: about 400 years