People have been captivated by horses for a long time; they appear more than any other animal in cave paintings dating back 30,000 years. But how did horses make the journey from wild animals to ones humans could hitch themselves to and even ride, determining the fate of civilizations and dramatically altering history? Equids originally evolved in North America and, sometime after 4 million years ago, ancient equid species began trotting across the Bering land bridge, eventually spreading through Eurasia and into Africa, diversifying into the lineages that would lead to modern-day horses, donkeys, and zebras. Early humans, including generations of the first people to live in the Americas, hunted wild horses, sometimes fashioning their bones into tools. Then, between 15,000 and 5,000 years ago, likely because of a changing climate, hunting by humans, and competition with bison, horses disappeared from the American archaeological record. But they’d be back eventually.
In the meantime, on the other side of the world around 2,000 BCE, something very consequential happened: people on the western Eurasian steppe domesticated horses. By then, people in western Asia had already domesticated many animals and begun using some of them to pull carts. But, because horses were generally faster and more difficult to control, steppe people developed a bridle-and-bit system and chariots with lighter, spoked wheels. Horses were soon integrated into many ancient cultures. In contrast with horse-drawn charioteering, horseback riding appears to have been less common at first. Archaeological evidence suggests that people who did mount horses during this early stage did so without structured saddles or stirrups. This sometimes altered or damaged the skeletons of riders and horses alike. People continued breeding for less aggressive horses with greater endurance and weight-bearing abilities. And they developed techniques and tools for improved control and comfort.
After around 1000 BCE, cavalry appeared in combat across much of Asia. Riders of steppe and desert cultures became renowned for their prowess on horseback. Ceremonial horse sacrifice also made its way into the funerary traditions of some cultures. One royal Scythian burial site from around the 9th century BCE contained the remains of approximately 200 horses fitted with riding gear. Officials in ancient China recognized how advantageous horses were for their neighbors and some coveted larger numbers of them for their own empire. Around 100 BCE, the Chinese emperor reportedly ordered a 30,000-man army west that laid siege to a city and had its king killed—all for 3,000 of the so-called “heavenly horses” of Ferghana.
Between the 4th and 8th centuries CE, steppe horsemen spread riding technologies like stirrups across cultures. And nomadic groups eventually coalesced into unstoppable forces on horseback. The Mongol Empire rose to power in the 13th century, and raided, traded, and toppled empires over previously unthinkable distances. They developed a horse-backed postal relay system that stretched more than 60,000 kilometers. Their imperial successes relied on the well-being of their horses—and leaders knew it. In 1252, before launching his next military campaigns, Möngke Khan sent officials ahead to prohibit cattle grazing so there’d be plentiful pastureland for their steeds.
Horses continued to spread, eventually spurring equestrian empires reaching south of the Sahara. By the mid-14th century, the Mali Empire was said to have had a cavalry of more than 10,000 that controlled some 1 million square kilometers of West Africa. And by 1500, horses were finally reintroduced to the Americas. They appear to have escaped Spanish control rapidly as Indigenous people from the Pampas to the Great Plains exchanged them via expansive trade networks. Colonization and trade spread horses even further around the globe. Well into the 20th century, horses were a widespread and essential means of travel and transport. However, this came with its own set of problems, such as hygiene and animal welfare, especially in cities. The introduction of non-living modes of transportation, such as automobiles, transformed many human-hubs. Despite this, people have maintained their multifaceted relationships with horses, from Mongolia to Montana, engaging in activities such as riding, herding, racing, or simply admiring them.