If one were to name the spiritual pillars of the Han dynasty,
then aside from the Son of Heaven himself, there was one envoy no one could avoid mentioning—Su Wu.
Famed among the Xiongnu, his merit illuminated the Han court: sent to distant lands, he never disgraced his mission, never diminished the dignity of his state.
Wang Xuance, however, represented a completely different kind of envoy.
He too suffered humiliation.
He too treated life and death as secondary.
But unlike Su Wu, Wang Xuance seemed never to have entertained the idea of enduring quietly from the very beginning.
He spent not a single Tang soldier.
He wielded imperial prestige to mobilize the troops of tributary states—and brought down punishment like a thunderbolt.
"With talent like that, it's a waste to keep him as an envoy."
That was Zhang Fei's immediate reaction.
Fa Zheng shook his head.
"In Tang, military talent is abundant. If he entered the regular army, he might instead fade into mediocrity. It would be hard for him to stand out the way he did."
Zhang Fei thought it over and had to agree.
Tang truly never lacked capable generals. In fact, the emperor himself was among the most formidable of them.
Even nomad leaders were willing to stake their lives for Tang—some, khagans no less, abandoning their thrones to serve as Tang commanders.
In such an environment, where everyone raced to distinguish themselves, it was genuinely difficult for a general to rise above the rest.
"No wonder Tang produces generals like shooting stars," Zhang Fei muttered, "all willing to gamble everything."
Take the campaign against Khotan, for example. From the map alone, it was clear: Kucha had already fallen, and the connection between Western Turkic forces and Khotan had been severed.
They could have consolidated Kucha first, then advanced on Khotan step by step—a far safer approach.
Yet the Tang commander did the opposite. Chasing merit without regard for his own safety, he led barely fifty men straight for the capital, forcing submission at swordpoint.
That desperation to achieve distinction was unmistakable.
Still, Fa Zheng found something puzzling.
"Wang Xuance didn't command Tang troops," he said. "Yet he advanced like a hot knife through butter."
"A land so wealthy—how could it collapse so easily?"
[ Lightscreen]
[Since we're already talking about Tianzhu, it's worth taking a detour to explain this remarkable place.
As for why Tianzhu's military strength was so poor, the caste system sapping the fighting spirit of lower soldiers is only part of the reason.
The Indian plains truly were a gift of nature—capable of supporting 1.4 billion people with ease, even producing surplus grain for export. But every advantage has its cost.
The most critical issue was this: iron was plentiful, but coal was not.
Without coal, they couldn't develop technologies like folded steel, pattern-welded steel, or blast-and-quench methods. As a result, they lacked high-quality armor and weapons.
In the age of cold weapons, everyone knows this: swords can be toys. Armor is life.
Privately owning bows or crossbows meant punishment at best, exile at worst. Privately owning armor could mean execution—or even extermination of one's clan.
That alone shows how decisive armor was.
The absence of armor didn't just weaken individual soldiers. It also prevented the central army from maintaining a technological gap over regional forces, making long-term dynastic control unstable.
That was one major reason Wang Xuance's campaign advanced so effortlessly.
Another was geography. The land was simply too fertile—vast, arable plains everywhere, leaving little terrain that could be defended.
In familiar terms: India was a textbook battleground of four open fronts.
And then there was the most fatal flaw of all—India did not produce horses.
They couldn't even field rudimentary light cavalry.
The result was inevitable. Persians, Macedonians, Greco-Bactrians, Parthians, Yuezhi, Hephthalites, Mongols—one after another, they passed through the Khyber Pass and swept across Tianzhu like war gods.
Under those conditions, Wang Xuance's victories were only natural.
As for how Wang Xuance was treated afterward, later generations often disagree.
One argument claims that although he destroyed a kingdom, he gained little, while Tubo profited instead—leaving Li Shimin displeased and leading to Wang Xuance's harsh treatment. Let's unpack that.
During the Zhenguan era, Tubo wasn't particularly interested in India. The route was simply too difficult.
That's why Songtsen Gampo only lent 1,200 troops. Had Tubo truly wanted to intervene, fielding ten thousand would not have been difficult.
Historically, Tubo's incursions into India came only after the An Lushan Rebellion—once Tubo had already occupied Hexi and the Western Regions. Even then, Tang territory was far more tempting than Tianzhu.
Moreover, late Zhenguan marked the honeymoon period between Tang and Tubo. Their falling-out wouldn't come until fifteen years after Wang Xuance destroyed that kingdom.
There's further evidence. In early Kaiyuan, the state of Qieshimi in Eastern Tianzhu sent an embassy to Emperor Xuanzong, carrying a letter that read:
"Since our founding, we have been subjects of the Heavenly Khagan… I personally guard the five great routes between Central Tianzhu and Tubo, forbidding passage… Should the Heavenly Khagan's army reach Bolü, even at two hundred thousand strong, we can supply their provisions. Our land also holds the Mahāpadma Dragon Pool, and we wish to build a shrine for the Heavenly Khagan."
The message was clear: they recognized the authority of the Heavenly Khagan, continued blocking Tubo's access to Tianzhu, and even offered to supply an army of two hundred thousand—requesting only that Tang keep its forces under that number.
"Willing to build a shrine" meant something else as well: they were prepared to host Tang garrisons.
As for Wang Xuance himself, it's hard to call his treatment harsh.
Before departing, he was a Right Guard Commandery Secretary, upper seventh rank.
After returning, he was promoted to Court Gentleman for Ceremonial Service, lower fifth rank.
Tang officialdom ran on nine grades and thirty steps, with annual evaluations. Only after four years of satisfactory reviews could one advance a step; exceptional merit allowed faster promotion. Posts above fifth rank required imperial approval.
Within that system, Wang Xuance jumped five ranks in one move—and fifth rank onward meant the emperor personally took note.
If anyone was truly unkind to Wang Xuance, it was fate.
The physicians he brought back from Tianzhu failed to cure Erlang's illness.
Just as he had entered imperial favor, the emperor died.
Worse still—the emperor had taken medicine from those very doctors.
Wang Xuance's career was like a ship that had only just set sail—only to sink immediately.]
Li Shimin felt he had underestimated this land. His eyebrows rose uncontrollably, and he even hooked a finger in his ear.
"How many people did you say?"
The explanation hardly needed repeating—the Light Screen had been plain enough. Still, disbelief lingered.
"One point four billion… and they can still export grain?"
By contrast, another figure surfaced in his mind.
"I recall that in the fourth year of Daye, the Central Plains had forty-six million people—Sui at its height. Not even fifty million."
Du Ruhui stepped forward.
"These are figures from later ages. With their technology and farming methods far beyond ours, sustaining hundreds of millions would be possible."
Even so… Li Shimin found it hard to accept.
In Daye's fifth year, there were nearly nine million registered households. By early Tang, rough counts showed barely two million.
At first glance, it seemed thirty million had perished in the chaos of Sui's fall—but Li Shimin had studied this carefully.
In the fourth and fifth years of Daye, Emperor Yang had aggressively uncovered hidden households and forced brothers to split families to increase tax revenue.
Taxes rose sharply—but in hindsight, Li Shimin believed this marked the true beginning of disaster.
That was why, early in his reign, he amended the law: if parents were alive, children who split households would be punished.
He ignored proposals to investigate hidden households, instead issuing incentives for childbirth, letting the people recover.
Yang's methods were flawed—but they did clarify population numbers. Compared to that…
"Nearly twenty times a Daye-era population…" Fang Xuanling exclaimed.
Du Ruhui understood his old friend perfectly.
"One wonders what methods of governance such a state employed."
On the other side, the generals were already restless.
Li Shiji summed it up neatly:
"No armor. No weapons. No horses. No defensible terrain."
His eyebrows rose, mirroring the emperor's.
"Isn't that a place one could attack at will?"
Looking at the long list of conquerors who passed through the Khyber Pass, Li Shiji felt a surge of envy.
So many came and went—why couldn't Huaxia be one more?
Su Dingfang nodded vigorously. Zhangsun Wuji, however, shot him a sharp look.
This prize—I noticed it first.
When even a small Eastern Tianzhu state dared promise provisions for two hundred thousand troops, Changsun Wuji decided he had to press the issue.
"General Maogong has already destroyed Xueyantuo," he said. "Why not make up for Your Majesty's regret and revisit Goguryeo?"
Li Shiji straightened completely, refusing to yield an inch.
"Once the Tang navy is established, a surprise strike by sea and land together will crush Goguryeo in an instant."
"Then we turn west. Cavalry by transport ship—Tianzhu would fall in no time."
Zhangsun Wuji's round face flushed crimson. He jabbed a finger at Li Shiji twice, then dropped his hand in frustration.
Currently without office, his voice simply didn't carry weight. Perhaps he should hint to His Majesty about an early reinstatement?
He, Zhangsun Wuji, also wished to serve the state.
Li Shimin paid it little mind. His old ministers argued, but the final decision always rested firmly with him.
As for Wang Xuance's fate, Li Shimin could only sympathize—and do little else.
After all, by then he was already dead. What could be done?
And besides, Wang Xuance had been employed early this time. By that measure, there were no regrets.
Li Shimin stroked his slightly curled beard, mulling over the casual remark on the Light Screen.
Stationing troops in another state—beyond supplying provisions…
Shouldn't they also be paying Tang for the privilege?
[ Lightscreen]
[Because of Erlang's sudden death, Wang Xuance's soaring career came to an abrupt halt.
And because of that same sudden death, the Turks were once again—yet again—preparing to rebel.
This time, the central figure was the Tang general Ashina Helu—our previously mentioned "Little Helu."
Fleeing pursuit by the Western Turkic Khagan, he defected to Tang and gained merit as a guide during the destruction of Kucha.
At the victory celebration, Erlang favored him greatly—personally draping his own robe over Helu's shoulders, granting him the post of Left Xiaowei General and Protector of Yaoci, with exceptionally generous emoluments and honors."
But people differ.
Some, upon Erlang's death, wept and wished to die with him—like Ashina She'er, who even gave up being khagan.
Others, the moment Erlang died, thought only of rebelling and reclaiming the khaganate—like our exchange student, Little Helu.
From this point on, the fall of the Western Turks truly began.
And the man who had been sweeping streets in Chang'an for thirty years—Su Dingfang—finally strode onto the stage of history with thunderous force.]