The Shattered Empire: An Lushan’s Revolt and Its Immediate Consequences

The An Lushan Rebellion (755–763) marked a catastrophic turning point for the Tang Dynasty, transforming a flourishing, cosmopolitan empire into a fractured realm plagued by internal strife and external threats. General An Lushan’s betrayal exposed the vulnerabilities of the Tang military system, particularly its reliance on regional commanders of non-Han origin. The rebellion’s suppression came at a steep price: to secure victory, the Tang court granted autonomous power to former rebel generals like Tian Chengsi and Li Baochen, allowing them to govern key northern provinces. This compromise sowed the seeds of fanzhen (regional warlord) dominance, creating a parallel power structure that would haunt the dynasty for over a century.

The Fanzhen Problem: A Century of Decentralization

Post-rebellion, the Tang state underwent radical restructuring. The once-mighty frontier armies (jian’er) were redeployed inward, becoming tools for domestic power struggles. Military governors (jiedushi) expanded their authority, controlling taxation, appointments, and even inheritance—rendering provinces like Weibo and Chengde virtually independent. Despite this, the Tang court retained vital economic lifelines: the Grand Canal ensured grain and revenue flowed from the prosperous Yangtze Delta to the capital, while salt monopolies (pioneered by officials like Liu Yan) funded central operations.

Emperor Xianzong (r. 805–820) launched the most successful counteroffensive against the fanzhen, temporarily subduing rebellious regions through campaigns like the 817 Siege of Caizhou. Yet these victories proved ephemeral; the underlying social and economic structures enabling warlordism persisted. By the 9th century, the court’s control had eroded to a ceremonial shell in many areas.

External Perils: Tibet and the Shifting Borderlands

As internal cohesion weakened, external pressures mounted. The Tibetan Empire exploited the Tang’s distraction during the An Lushan crisis, seizing the Hexi Corridor and even sacking Chang’an in 763. This loss severed China’s ties to Central Asia, though later alliances with the Uyghurs and Nanzhao Kingdom helped counterbalance Tibetan power. The 821 Treaty of Qingshui formalized a fragile peace, but Tibet’s subsequent collapse in the 850s allowed local leaders like Zhang Yichao to reclaim Dunhuang and establish the semi-independent Guiyi Army.

Meanwhile, new threats emerged: the Uyghur Khaganate fragmented under Kirghiz attacks (840), while Nanzhao expanded into Southeast Asia. Most ominously, the Khitan people—future founders of the Liao Dynasty—began consolidating power in Manchuria.

The Rise of the Eunuchs: Protectors and Undertakers of Imperial Power

With aristocrats diminished and imperial princes confined to the “Sixteen Estates,” eunuchs emerged as the emperor’s most trusted agents. Initially military supervisors like Yang Sixu (d. 740), they gained unprecedented influence after Dezong entrusted the Shence Army—the dynasty’s last loyal force—to eunuch commanders in 796. By the 9th century, the “Four Nobles” (two Shence Army generals and two Privy Council eunuchs) controlled appointments, policy, and even imperial succession.

This system proved disastrously brittle. The 835 Sweet Dew Incident—a failed coup against eunuchs by Emperor Wenzong—led to mass purges of scholar-officials. Later, eunuch factions backed rival chancellors in the Niu-Li Partisan Strife (808–846), paralyzing governance. Their final extermination during Zhu Wen’s 903 coup left the Tang without its last power base, hastening the dynasty’s collapse.

The Road to Collapse: Rebellions and the Fall of Chang’an

The late Tang witnessed systemic failures on all fronts. The 868 Guiyang Mutiny exposed military discontent, while the 875–884 Huang Chao Rebellion delivered the deathblow. Huang’s forces—a mix of salt smugglers, exam failures, and drought refugees—sacked Guangzhou (879), massacring its cosmopolitan merchant communities, before turning north. Their 880 occupation of Chang’an culminated in a vengeful massacre that destroyed the capital’s cultural legacy. Though defeated, the rebellion shattered the Tang’s remaining authority, paving the way for the Five Dynasties era.

Legacy: The Tang’s Enduring Paradox

The post-An Lushan Tang presents a paradox: a weakened state that nonetheless adapted creatively to survive. Its fiscal reforms (like the Two-Tax System) influenced later dynasties, while its struggles with decentralization prefigured Song and Ming challenges. Yet the costs were staggering—the loss of Central Asia, the rise of militarized provinces, and the tragic devolution of its cosmopolitan ideals. In the end, the Tang outlived many of its rivals but succumbed to the very forces it had unleashed to survive.