The Foundations of a Multi-Ethnic Empire

The Tang Dynasty (618–907 CE) emerged from centuries of migration, conflict, and assimilation during the tumultuous period of the Wei, Jin, and Southern and Northern Dynasties. Unlike the Han Dynasty, which preceded it, the Tang was a truly multi-ethnic empire, shaped by the complex interplay of nomadic and sedentary cultures across East Asia.

By the time the Tang was established, many ethnic groups that had settled in the Central Plains—the heartland of Chinese civilization—had already undergone significant Sinicization. Though they retained their ethnic identities, their cultural distinctiveness had faded through generations of interaction with Han Chinese society. This phenomenon was not unique to the Tang; throughout pre-modern Chinese history, conquerors from the steppe often found themselves culturally conquered by the civilization they sought to rule.

The Steppe and the Silk Road: Tang’s Northern Frontier

### The Rise and Fall of the Turkic Khaganates

The Tang’s most formidable neighbors were the Turkic peoples, who dominated the northern steppes. The Turks, originally vassals of the Rouran Khaganate, rose to power under Bumin Qaghan (also known as Ilterish Qaghan), who defeated the Rouran in 552 CE and established the First Turkic Khaganate.

By the Sui Dynasty (581–618), the Turks had split into Eastern and Western Khaganates. The Eastern Turks, though temporarily subdued by Sui diplomacy and military campaigns, regained strength during the chaos of the Sui collapse. They even besieged Emperor Yang of Sui at Yanmen Pass and later extracted tribute from rebel factions—including Li Yuan, the founder of the Tang.

Tang’s relationship with the Eastern Turks remained fraught. In 626, shortly after Emperor Taizong (Li Shimin) ascended the throne, the Turks marched to the Wei River, forcing the humiliating “Wei River Alliance.” This event left a deep mark on Taizong, who later seized an opportunity for revenge.

### The Collapse of the Eastern Turks

In 629–630, a combination of natural disasters (severe snowstorms) and internal rebellions (led by the Xueyantuo and Uyghurs) weakened the Eastern Turks. Emperor Taizong dispatched generals Li Jing and Li Shiji to deliver the final blow, capturing the Turkic ruler Illig Qaghan. This victory marked a turning point, elevating the Tang as the undisputed hegemon of East Asia.

However, Turkic power resurged in the late 7th century under the Second Turkic Khaganate, which harassed the Tang until its eventual destruction by the Uyghurs in 744.

The Uyghurs: From Vassals to Overlords

The Uyghurs, originally subjects of the Turks, rose to prominence after aiding the Tang against the An Lushan Rebellion (755–763). Their cavalry played a decisive role in recapturing the Tang capitals, but their arrogance and demands for exorbitant tributes strained relations. The Tang even sent imperial princesses to marry Uyghur khans—a rare honor—highlighting their strategic importance.

By the 9th century, the Uyghur Khaganate declined due to internal strife and Tang counterattacks, fragmenting into migratory groups.

The Northeast: Khitans, Mohe, and the Parhae Kingdom

### The Khitans: A Steppe Power in the Making

The Khitans, ancestors of the later Liao Dynasty, emerged from the Xianbei confederation. During the Tang, they alternated between submission and rebellion. Notably, in 696, Khitan revolts forced Empress Wu Zetian to ally with the Turks to suppress them.

By the late Tang, the Khitans grew stronger under Yelü Abaoji, who would later found the Liao Dynasty. Their influence was so vast that in some languages, “Cathay” (derived from “Khitan”) became synonymous with China.

### The Mohe and the Parhae Kingdom

The Mohe tribes, particularly the Sumo and Heishui branches, inhabited Manchuria. The Sumo Mohe leader, Dae Jo-yeong, established the Parhae Kingdom (698–926), which mirrored Tang administration but occasionally clashed with the empire. A dramatic episode involved Dae Jo-yeong’s sons—one pro-Tang, the other anti-Tang—leading to a maritime attack on Dengzhou (modern Shandong).

Despite conflicts, Parhae maintained cultural ties with the Tang until its destruction by the Khitans.

The Western Frontier: Tang and the Silk Road

### The Anxi and Beiting Protectorates

The Tang’s Western Regions (modern Xinjiang and Central Asia) were a patchwork of oasis city-states. To manage this vast territory, the Tang established the Anxi Protectorate (640) and later the Beiting Protectorate (702), divided along the Tianshan Mountains.

### The Western Turks and the Battle for Supremacy

The Western Turks, organized into “Ten Tribes,” were formidable but plagued by infighting. In 657, Tang general Su Dingfang crushed their leader Ashina Helu, securing Tang dominance. However, by the 8th century, the Türgesh tribe filled the power vacuum, alternately allying with and opposing the Tang.

The Tibetan Plateau: Tang and Tibet’s Fierce Rivalry

### The Rise of the Tibetan Empire

Under Songtsen Gampo (r. 618–650), Tibet unified and expanded, clashing with the Tang over the Tarim Basin. The Tang suffered devastating defeats, such as the Battle of Dafeichuan (670), where 100,000 Tang troops were annihilated.

Tibet exploited the An Lushan Rebellion to seize the Hexi Corridor and the Four Garrisons of Anxi, cutting off Tang access to the Western Regions.

### The Tuyuhun: A Buffer State’s Tragic Fate

The Tuyuhun, a Xianbei-descended kingdom, served as a buffer between Tang and Tibet until its annexation by Tibet in 663. Its exiled rulers became Tang vassals, a symbolic presence long after their state’s fall.

The Southwest: Nanzhao’s Shifting Allegiances

Nanzhao, a kingdom in Yunnan, oscillated between Tang and Tibetan influence. After rebelling in 750 due to Tang extortion, it allied with Tibet before returning to the Tang fold in the 790s. Its eventual collapse in 902 mirrored the Tang’s own decline.

Legacy: The Tang’s Enduring Influence

The Tang’s multi-ethnic policies—incorporating Turkic, Uyghur, Tibetan, and Manchurian elements—created a cosmopolitan golden age. Its legacy lives on in China’s cultural memory as a model of openness and adaptability, a stark contrast to later inward-looking dynasties.

From the Silk Road’s bustling markets to the battlefields of Central Asia, the Tang’s story is one of conquest, diplomacy, and cultural synthesis—an empire where “Chinese” identity was constantly redefined by its interactions with the wider world.