Beijing, the political, cultural, military, and commercial centre of the empire, was the capital city of the last three dynasties of China; it was the last imperial capital built in China's history. Continuing and improving upon the construction and planning traditions of earlier dynasties, Beijing embodied some of the highest achievements in the field of city planning during the Ming and Qing dynasties.《中国古代城市地理》, p. 230"Chinese Ancient Cities Geography", p. 230 The construction of the fortification system borrowed ideas from Dadu of the Yuan era and Nanjing of the Ming era, and typified the Yuan and post-Yuan pre-Republican era city planning styles. It is the final example of China's 3,200 year-long square-shaped dynastical city planning style. It closely matched the scale of Chang'an of the Tang dynasty. The city was carefully planned during the early Ming dynasty, with a central axis running through the midpoints of the northern and southern walls, dividing the city into two equal parts to fulfil the Confucian ideals of "Golden mean"(居中不偏) and "不重不威". The Forbidden city was at the centre of it all, with Longevity Mount (Jingshan) just north of the palaces. The Imperial city, surrounding the palaces, provided everything necessary for the maintenance of the Emperor's lifestyle within the Forbidden city. The southern sections of the city were allocated to officials and bureaucrats, while the Inner and Outer city served as extra protection for the Imperial city and the palace complex. The streets, avenues, and boulevards of the city were straight and wide, presenting the imperialistic ideal of order. Everything, including Buddhist temples, Taoist temples, business districts, parks, and imperial family residences were all planned in accordance with the city's layout, its order being much stricter than that of Dadu, and larger in scale.《中国古代建筑史》第四卷，p. 31"History of Ancient Chinese Architecture" Volume IV, p. 31 The design of Beijing's fortifications borrowed elements from the Wujing Zongyao of the Northern Song dynasty (960–1127) and the already highly developed fortification construction expertise of the Southern Song (1127–1279). All of the structures used bricks and stones as foundations rather than rammed earth, including the watchtowers, the corner guard towers, the barbicans, the enemy sight towers, and the sluice gate towers. Forming both a planar and spatial defence for the city, it was dynastical China's best fortified city defence system, displaying the late dynastical China's greatest achievements in city fortification design.《中国古代城市地理》, p. 84"Chinese Ancient Cities Geography", p. 84
