The Ambitious Rise of a Ruthless Leader

In the sixth year of Emperor Hui’s reign (192 BCE), Empress Lü, who had consolidated imperial power and ruled with unchallenged authority, received an unexpected and audacious marriage proposal from Modu, the formidable chanyu (ruler) of the Xiongnu. The letter bluntly stated that since both were widowed, they should unite in matrimony. Enraged by this brazen insult, Empress Lü and her court erupted in calls for war.

But who was Modu, and why did he dare provoke the Han Empire so openly?

Modu was no ordinary ruler. Originally the crown prince under his father, Touman Chanyu, he survived an assassination attempt orchestrated by his own father, who favored a younger son from a favored consort. Sent as a hostage to the Yuezhi people, Modu narrowly escaped execution when Touman attacked the Yuezhi, stealing a horse and fleeing back to his people. Recognizing his son’s cunning, Touman granted him command of 10,000 cavalry.

Modu then devised a chilling method to ensure absolute loyalty. He created a whistling arrow (mingdi) and ordered his troops to shoot wherever it landed—failure meant death. First, he tested them by shooting game, executing those who hesitated. Next, he targeted his own horse, then his favorite concubine, and finally his father’s prized steed. When his men obeyed without question, Modu knew they were ready.

During a hunting expedition, Modu turned his whistling arrow on Touman. His loyal cavalry followed suit, killing the chanyu instantly. Modu then slaughtered his stepmother, half-brother, and dissenting nobles, declaring himself the new ruler.

The Strategic Genius of Modu Chanyu

Upon his ascension, the neighboring Donghu kingdom, sensing weakness, demanded Touman’s legendary thousand-li horse. Modu’s advisors protested, but he yielded, claiming, “Why begrudge a horse to a neighbor?” Emboldened, the Donghu next demanded one of Modu’s wives. Again, he complied, enraging his court but biding his time.

When the Donghu demanded a vast stretch of neutral land, Modu’s advisors wavered. This time, he erupted: “Land is the foundation of a nation—how can we surrender it?” Executing the hesitant ministers, he launched a surprise attack, annihilating the Donghu and seizing their people and livestock.

Modu then expanded westward, crushing the Yuezhi, and southward, reclaiming territories lost to the Qin general Meng Tian. By the time of the Han dynasty’s founding, Modu commanded 300,000 cavalry—a force rivaling the Han itself.

The Han Dynasty’s Humiliation: The Siege of Baideng

In 200 BCE, Han Emperor Gaozu (Liu Bang) led a 320,000-strong army against the Xiongnu after their ally, King Xin of Han, defected. Modu feigned retreat, luring Liu Bang into a trap at Baideng (modern Datong). Surrounded by 400,000 Xiongnu horsemen, the emperor was stranded for seven days without supplies or reinforcements.

The Han strategist Chen Ping devised a desperate plan: bribing Modu’s consort with gifts and a warning that Han beauties would soon arrive, threatening her status. The ploy worked—Modu, suspicious of his allies’ delays, withdrew.

The Controversial Policy of Heqin (Marriage Alliance)

After Baideng, Liu Bang sought a lasting solution. Advisor Liu Jing proposed heqin—marrying a Han princess to Modu to secure peace. Though initially receptive, Liu Bang’s wife, Empress Lü, refused to send their daughter. Instead, a fake “princess” was sent, marking the first of many humiliating tributes.

While criticized as appeasement, heqin bought the Han time to recover, fostering cultural exchange and economic dependence.

Empress Lü’s Diplomatic Restraint

Years later, Modu’s insulting proposal reignited Han fury. General Fan Kuai vowed to crush the Xiongnu with 100,000 troops, but the former Chu general Ji Bu—a man once hunted by Liu Bang—countered: “Fan Kuai deserves death for such arrogance!” He reminded the court of Baideng’s lessons and the empire’s exhaustion.

Empress Lü, though furious, heeded Ji Bu’s wisdom. She replied to Modu with humility, citing her old age, and sent gifts. Modu, impressed, reciprocated with horses, restoring peace.

Legacy and Historical Impact

Modu’s reign transformed the Xiongnu into a nomadic superpower, foreshadowing later conquerors like Genghis Khan. For the Han, early defeats and heqin underscored military weakness, but the respite allowed eventual resurgence under Emperor Wu.

Empress Lü’s restraint, though at odds with her ruthless domestic politics, preserved Han-Xiongnu stability—a testament to pragmatic statecraft amid humiliation. The era’s tensions would shape East Asian geopolitics for centuries, illustrating the delicate balance between pride and survival in ancient diplomacy.