Question: How many square miles is the city where the Yongle emperor greeted the person to whom the edict was addressed?

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: Nanjing
Nanjing, with a total land area of 6,598 square kilometres (2,548 sq mi), is situated in the heartland of drainage area of lower reaches of Yangtze River, and in Yangtze River Delta, one of the largest economic zones of China. The Yangtze River flows past the west side and then north side of Nanjing City, while the Ningzheng Ridge surrounds the north, east and south side of the city. The city is 300 kilometres (190 mi) west-northwest of Shanghai, 1,200 kilometres (750 mi) south-southeast of Beijing, and 1,400 kilometres (870 mi) east-northeast of Chongqing. The downstream Yangtze River flows from Jiujiang, Jiangxi, through Anhui and Jiangsu to East Sea, north to drainage basin of downstream Yangtze is Huai River basin and south to it is Zhe River basin, and they are connected by the Grand Canal east to Nanjing. The area around Nanjing is called Hsiajiang (下江, Downstream River) region, with Jianghuai (江淮) stressing northern part and Jiangzhe (江浙) stressing southern part. The region is also known as Dongnan (東南, South East, the Southeast) and Jiangnan (江南, River South, south of Yangtze).
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
In order to seek out the Karmapa, the Yongle Emperor dispatched his eunuch Hou Xian and the Buddhist monk Zhi Guang (d. 1435) to Tibet. Traveling to Lhasa either through Qinghai or via the Silk Road to Khotan, Hou Xian and Zhi Guang did not return to Nanjing until 1407. [SEP] Knowledge 3: Nanjing
Nanjing, with a total land area of 6,598 square kilometres (2,548 sq mi), is situated in the heartland of drainage area of lower reaches of Yangtze River, and in Yangtze River Delta, one of the largest economic zones of China. The Yangtze River flows past the west side and then north side of Nanjing City, while the Ningzheng Ridge surrounds the north, east and south side of the city. The city is 300 kilometres (190 mi) west-northwest of Shanghai, 1,200 kilometres (750 mi) south-southeast of Beijing, and 1,400 kilometres (870 mi) east-northeast of Chongqing. The downstream Yangtze River flows from Jiujiang, Jiangxi, through Anhui and Jiangsu to East Sea, north to drainage basin of downstream Yangtze is Huai River basin and south to it is Zhe River basin, and they are connected by the Grand Canal east to Nanjing. The area around Nanjing is called Hsiajiang (下江, Downstream River) region, with Jianghuai (江淮) stressing northern part and Jiangzhe (江浙) stressing southern part. The region is also known as Dongnan (東南, South East, the Southeast) and Jiangnan (江南, River South, south of Yangtze).
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: Nanjing
A monument to the huge human cost of some of the gigantic construction projects of the early Ming dynasty is the Yangshan Quarry (located some 15–20 km (9–12 mi) east of the walled city and Ming Xiaoling mausoleum), where a gigantic stele, cut on the orders of the Yongle Emperor, lies abandoned, just as it was left 600 years ago when it was understood it was impossible to move or complete it.

Answer: 2,548 sq mi