The Emperor's Obsession
In the 2nd century BCE, the Chinese Emperor Wu of Han developed a fixation on a superior horse breed from the Fergana Valley, a region known to the Chinese as Dayuan. Reports from his diplomat, Zhang Qian, described these animals as powerful and fast, calling them tiānmǎ (天馬), or "Heavenly Horses." Ancient accounts claimed these horses "sweat blood," a phenomenon that added to their mystique. This trait is now understood by parasitologists to be the result of a nematode, Parafilaria multipapillosa, which burrows under the skin and causes bleeding nodules, especially during exertion.
Emperor Wu’s desire for these horses was not for their beauty; he needed them to create a formidable cavalry to fight the nomadic Xiongnu, whose mounted archers harassed the Han Dynasty's borders. After diplomatic missions and trade offers failed, the emperor launched two massive military campaigns. The first, in 104 BCE, ended in failure. A second, larger expedition in 102 BCE succeeded in besieging the capital of Dayuan. The Han forces returned to China with only a few dozen of the prized "Heavenly Horses" and around 3,000 other mounts of lesser quality. This conflict, known as the War of the Heavenly Horses, successfully expanded Han influence into Central Asia and established the trade network that would become the Silk Road.