Question: How long was the place where the Yongle Emperor greeted who the Ming court thought representatives were sent by the capitol of the city in which Guangling District is located?

Knowledge 1: Guangling District
Guangling District () is one of three districts of Yangzhou, Jiangsu province, China. The district includes the eastern half of Yangzhou's main urban area (including Yangzhou's historic center within the former city wall), and the city's eastern suburbs. The other half of the city's main urban area is in Hanjiang District. [SEP] Knowledge 2: Sino-Tibetan relations during the Ming dynasty
Despite this glowing message by the Emperor, Chan writes that a year later in 1446, the Ming court cut off all relations with the Karmapa hierarchs. Until then, the court was unaware that Deshin Shekpa had died in 1415. The Ming court had believed that the representatives of the Karma Kagyu who continued to visit the Ming capital were sent by the Karmapa. [SEP] Knowledge 3: 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 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: Guangling District
Guangling District () is one of three districts of Yangzhou, Jiangsu province, China. The district includes the eastern half of Yangzhou's main urban area (including Yangzhou's historic center within the former city wall), and the city's eastern suburbs. The other half of the city's main urban area is in Hanjiang District. [SEP] Knowledge 2: Sino-Tibetan relations during the Ming dynasty
Despite this glowing message by the Emperor, Chan writes that a year later in 1446, the Ming court cut off all relations with the Karmapa hierarchs. Until then, the court was unaware that Deshin Shekpa had died in 1415. The Ming court had believed that the representatives of the Karma Kagyu who continued to visit the Ming capital were sent by the Karmapa. [SEP] Knowledge 3: 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 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: Guangling District
Guangling District () is one of three districts of Yangzhou, Jiangsu province, China. The district includes the eastern half of Yangzhou's main urban area (including Yangzhou's historic center within the former city wall), and the city's eastern suburbs. The other half of the city's main urban area is in Hanjiang District. [SEP] Knowledge 2: Sino-Tibetan relations during the Ming dynasty
Despite this glowing message by the Emperor, Chan writes that a year later in 1446, the Ming court cut off all relations with the Karmapa hierarchs. Until then, the court was unaware that Deshin Shekpa had died in 1415. The Ming court had believed that the representatives of the Karma Kagyu who continued to visit the Ming capital were sent by the Karmapa. [SEP] Knowledge 3: 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 4: Nanjing
Over two centuries after the removal of the capital to Beijing, Nanjing was destined to become the capital of a Ming emperor one more time. After the fall of Beijing to Li Zicheng's rebel forces and then to the Manchu-led Qing dynasty in the spring of 1644, the Ming prince Zhu Yousong was enthroned in Nanjing in June 1644 as the Hongguang Emperor. His short reign was described by later historians as the first reign of the so-called Southern Ming dynasty.

Answer: about 400 years