5,000 Foot Soldiers Once Crushed 80,000 Cavalry! Why Did Central China Lose Dominance After the Tang Dynasty? The '3 Fatal Reasons' Explain Why Victory Became Impossible

Throughout China's long history, the struggle between northern nomadic tribes and the Central Plains dynasties has spanned multiple eras. From the Quanrong and Donghu of the pre-Qin period to later powers such as the Xiongnu, Wuhuan, Xianbei, and Rouran, these groups rose and fell in succession, frequently invading the Central Plains. Yet most ultimately met defeat, being crushed or absorbed by Central Plains powers like the Qin and Han dynasties. Historically, there was even the legendary battle in which Li Ling of the Western Han led 5,000 foot soldiers to defeat 80,000 Xiongnu cavalry.

However, history took a sharp turn after the Tang Dynasty. The northern nomadic tribes rapidly strengthened, gaining the ability to rival the Central Plains dynasties—and even dominate them on the battlefield. As a result, the era of territorial expansion and military glory seen during the Han and Tang dynasties came to an end. Behind this historical shift—where 'northern iron cavalry crushed the Central Plains'—lie three critical turning points.

In popular historical understanding, the Han Dynasty defeated the Xiongnu and performed the Fengshan ceremony at Langjuxu Mountain, while the Tang Dynasty destroyed the Turkic Khaganate and earned the title of 'Heavenly Khan.' The military prowess of the Huaxia people seemed unmatched. Yet after the Tang Dynasty, history reached a watershed moment. The Song Dynasty was repeatedly defeated by the Khitan and Jurchen, the Ming Dynasty suffered the Tumu Crisis in its mid-period, and ultimately, the Central Plains dynasties were completely overwhelmed by cavalry forces from the northern steppes.

Why could the Han and Tang dynasties subjugate nomadic tribes, while Central Plains armies after the Tang suddenly lost their former strength?

**Turning Point 1: The Stirrup Revolution—The End of the 'Li Ling Myth'**

According to historical analysis from Sohu.com, before the widespread use of stirrups, cavalry warfare had a fatal flaw. Riders could only maintain balance by gripping the horse’s belly with their legs, making close combat extremely dangerous. As a result, cavalry primarily relied on horseback archery. However, this tactic did not guarantee superiority against well-trained, precision-shooting infantry formations of the Central Plains.

The widespread adoption of stirrups during the Sui and Tang dynasties completely changed the rules of war. With stirrups providing stability, nomadic cavalry could now freely perform high-difficulty maneuvers such as mounted archery, high-speed charges, and close-quarters combat. When cavalry charged, the sheer kinetic force of the horses alone could devastate Central Plains infantry formations, creating a physical dominance of cavalry over infantry. This is the primary technical reason why legendary victories—like those of the Qin and Han eras, where small forces defeated large ones—were never repeated after the Tang Dynasty.

**Turning Point 2: Political Evolution—Khitan, Jurchen, and Mongol Administrative Systems**

Early nomadic societies existed as loose 'tribal confederations.' This decentralized political structure made it difficult to exert sustained strategic pressure on the Central Plains. For example, although the Xiongnu posed a serious threat to the Western Han under Modu Chanyu, they were quickly defeated and fragmented after splitting into eastern and western factions.

However, after the Tang Dynasty, the political organization of nomadic peoples evolved.

1. **High Centralization and Ethnic Identity**: The Khitan, Jurchen, and Mongol peoples gradually achieved large-scale unification in the north, adopting Central Plains institutions and establishing highly centralized administrative systems. This fostered strong governance and a powerful sense of ethnic unity.

2. **Sustained Warfare Through Unified Resources**: This political evolution enabled them to integrate and concentrate the resources of entire ethnic groups, launching organized, disciplined, and long-term military campaigns against the Central Plains. In the case of the Mongols, even before Genghis Khan’s rise, the steppes already hosted several powerful tribal organizations. Without this political evolution, even Genghis Khan could not have achieved unification within his lifetime.

**Turning Point 3: Self-Disarmament of the Central Plains—The Decline of Military Power Under Civilian Supremacy**

While northern nomadic tribes advanced technologically and politically, the Central Plains dynasties experienced a shift in governance philosophy that led to systemic military decline. The aftermath of the An Lushan Rebellion effectively 'castrated' the spirit of martial valor.

The Tang Dynasty’s regional military governor (jiedushi) system created the risk of warlordism. The An Lushan and Huang Chao rebellions later highlighted the dangers of military leaders gaining too much power. In response, Emperor Taizu of the Song Dynasty formally established the policy of 'prioritizing civil over military affairs' to consolidate imperial authority.

Society increasingly valued the ideal of 'excellence in study leads to officialdom.' The best talents pursued the imperial examinations and literary arts, no longer willing to take up arms and expand territory. Over-reliance on civilian bureaucracy and the strict suppression of the military class caused the Central Plains dynasties to gradually lose the martial spirit of the Han and Tang eras. Military development declined systematically, and military strength stagnated, making it increasingly difficult to resist the northern cavalry. It was not until the Ming Dynasty that attempts were made to manage the military outside the civilian bureaucracy, briefly restoring military prestige during campaigns like the Wanli Three Great Campaigns—but this revival was short-lived.