The day Vietnam burned the Mongol fleet.
On this day in 1285, the empire that had toppled China, sacked Baghdad, and ridden to the gates of Europe sent a war fleet up a quiet Vietnamese river, and stood on the banks watching it burn to the waterline.
This was the Mongol machine at the absolute height of its power. Kublai Khan, grandson of Genghis, sat atop the largest land empire the world has ever seen, and the small, stubborn kingdom of Dai Viet had refused to bow to him. So he sent a colossal army south, commanded by his own son Toghan and his hardened veteran general Sogetu. They swept over the border, brushed aside the defenders, and seized the capital. On every map in the Khan's court, the war was already won.
But the Vietnamese had not been beaten, they had stepped backward on purpose. Under two of the finest commanders of the age, Tran Hung Dao and Tran Quang Khai, they emptied their own capital, scorched the land behind them, and melted into the countryside. They let the vast Mongol army pour into a kingdom of ghosts, with nothing to eat, no one to fight, and supply lines stretching thinner by the day. Then they let the real enemy go to work: the brutal tropical heat, the rot, the fevers that gutted northern soldiers who had never known a climate like this.
When the invaders were sick, hungry, and overextended, the Tran struck. At the river port of Chuong Duong they fell on the Mongol fleet and tore it to pieces, sending fire ships and assault boats in among the anchored warships until the river was choked with smoke and wreckage. Those ships were the lifeline of the entire invasion, and in a single furious day that lifeline was cut. The recapture of the capital followed almost at once, and the proud general Sogetu was run down and killed in the chaos of the retreat.
The prince who led the assault, Tran Quang Khai, was so overcome by the victory that he composed a short poem in its honor, lines about seizing enemy spears at Chuong Duong ferry that Vietnamese schoolchildren still recite from memory more than seven hundred years later.
And the Mongols had not even learned their lesson. They came back a third time, and lost a third time, even more catastrophically, on the stake-filled waters of the Bach Dang River. The empire that had conquered half the known world could not break one determined people on their own rivers. June 14 was the day that legend first caught fire.