Map Introduction

I. Adjustments in Administrative and Military Systems

In the early Southern Song period, the Guangnan East Circuit (comprising most of modern Guangdong) maintained the late Northern Song administrative structure, with Guangzhou as its political center. A Military Commissioner served concurrently as the Prefect of Guangzhou, overseeing the circuit's military and administrative affairs. During the Shaoxing era (1131–1162 AD), to strengthen border defense, the court formally divided the Guangnan region into separate Eastern and Western Circuits, solidifying Guangzhou's role as the core of the Eastern Circuit. Militarily, a balance of power existed between the Commander's Office, the Fiscal Commission, and the Judicial Commission; however, the Prefect of Guangzhou retained emergency authority for "swift response in border defense." During the Qiandao era (1165–1173 AD), the Baojia mutual surveillance system was abolished due to its burden on the populace, and local policing responsibilities were transferred to archers and the巡检司 (Patrol and Inspection Bureaus).

II. Refinement of the Urban Defense System

The city of Guangzhou underwent multiple expansions during the Southern Song period:

• The Inner City (Central City): The defensive core originally built by Wei Jin in the 4th year of the Qingli era (1044 AD) of the Northern Song, which withstood Nong Zhigao's siege in the 4th year of the Huangyou era (1052 AD).
• The Eastern and Western Cities: Constructed successively by Lü Jujian and Cheng Shimeng in the 3rd year of the Xining era (1070 AD), forming a connected tripartite city layout. The Western City expanded to the area of modern Huifu West Road.
• The "Goose-Wing" Walls: Additional riverside defensive walls were added by Chen Xian in the 3rd year of the Jiading era (1210 AD) to protect the extramural commercial districts.

III. The Rise and Decline of Foreign Trade

Although Guangzhou retained its Maritime Trade Office, Quanzhou gradually rose to prominence from the mid-Southern Song period onward, leading to a relative decline in Guangzhou's share of trade. Records indicate that the annual revenue of the Maritime Trade Office in the early Southern Song was approximately 500,000 strings of cash, only about 80% of the revenue during the Zhiping era (1064–1067 AD) of the Northern Song. Exports primarily consisted of porcelain and silk textiles, while imports were dominated by spices and rhinoceros horns.

IV. Mongol Invasion and the End of the Regime

In the 1st year of the Jingyan era (1276 AD) under Emperor Duanzong, Mongol forces initially captured Guangzhou but temporarily withdrew due to local armed resistance. They recaptured the city in the 1st year of the Xiangxing era (1278 AD). Following the naval Battle of Yashan the next year, which marked the final collapse of the Southern Song, the Guangnan East Circuit was incorporated into the Yuan Dynasty as the Guangdong Circuit.

Conclusion

The evolution of the Southern Song's Guangnan East Circuit reflects the characteristics of decentralized local military-administrative authority, strengthened urban defenses, and a shifting trade focus. As the core of the Lingnan region, Guangzhou's city defense system and maritime trade institutions laid the foundation for the establishment of the later Guangdong Provincial Secretariat during the Yuan Dynasty.