Forty million years ago, horses first emerged in North America, but after migrating to Asia over the Bering land bridge, horses disappeared from this continent at least 10,000 years ago. For millennia, Native Americans traveled and hunted on foot, relying on dogs as miniature pack animals.

When Christopher Columbus brought two dozen Andalusian horses on his second voyage to the New World in 1493, he couldn’t have imagined how reintroducing the horse to North America would transform Native American life, especially for the buffalo-hunting Plains Indians, for whom the swift and loyal horse was a marriage made in heaven. (Some scholars believe horses never truly went extinct in North America and were used by Native American tribes prior to Columbus’ arrival.)

When Columbus and other Spanish explorers arrived in Hispaniola on horseback, the native Taíno of the Caribbean were terrified by what they saw as a half-man, half-beast, says Herman Viola, a curator emeritus at the Smithsonian Institution. “They had never seen a creature that had human beings riding on it.”

As more Native tribes encountered the horse, that initial fear gave way to awe for the animal’s speed and power. With the dog as their closest reference, Indians gave this mythical new creature names like “elk dog,” “sky dog” and “holy dog.”

“The Spanish quickly realized that the last thing they wanted was for Indians to have horses, because that would put them on equal footing,” says Viola, but that’s exactly what happened following the Pueblo Uprising of 1680. After enduring a century of harsh Spanish rule, the otherwise peaceful Pueblo Indians violently drove the Spanish from Santa Fe and captured their prized horses, which they then traded with neighboring tribes.

Horses quickly moved across trade routes to the Navajo, Ute and Apache, then to the Kiowa and Comanche of the southern Plains, and the Shoshone of the Mountain West. By 1700, horses had reached the Nez Perce and Blackfoot of the far Northwest, and traveled eastward to the Lakota, Crow and Cheyenne of the northern Plains. As horses arrived from the west, the first guns were being traded from the east. By the time of the French and Indian War in the 1760s, the armed and mounted Indian warrior was a formidable presence on the Great Plains.

Buffalo are big, strong and fast. Before horses came to the Plains, Native hunters pursued large herds on foot, but it was dangerous, difficult work with low odds of success. One technique was to startle and chase an animal toward a cliff or dropoff called a “buffalo jump.” Once wounded, the buffalo was easier to kill.

“When horses were introduced, the modes of hunting changed,” says Emil Her Many Horses, a curator at the Smithsonian’s National Museum of the American Indian and a member of the Oglala Lakota nation. “A favorite hunting horse could be trained to ride right into the stampeding buffalo herd.”

For the Plains Indians, the newfound speed and efficiency of hunting on horseback provided an abundance of high-quality meat, hides for tipis and clothing, and rawhide for shields and boxes. With the help of a draggable wooden sledge called a travois, horses could now transport entire villages and their possessions to follow the seasonal hunt.

“With the introduction of the horse, tribes gained more wealth, in a sense,” says Her Many Horses. Not only did tipis get bigger, but it lifted some of the daily burden from women, giving them more time to create works of art and sacred objects, many of them inspired by the horse.

Competition among the Plains Indians for the best hunting and war horses turned old allies into rivals, says Her Many Horses. More and better horses meant you could expand your hunting territory, bringing even more wealth to the tribe. Raiding and capturing enemy horses was a key tactic of inter-tribal warfare and was considered an “honorable” rite of passage for a young man trying to earn his place as a warrior.

Young men would walk miles to a rival camp, scout for the most-prized horses and wait for nightfall to make their move. Sneaking into an Indian village without alerting its canine security system was only the first challenge.

“Some of the horse owners were so concerned about their prize animals that they’d go to sleep with a rope tied to their wrist running under the tipi cover, so they could tug on it to make sure that horse was still safely there,” says Viola.

If the daring horse capturer was stealthy and lucky enough to make it out of the village alive—many didn’t—the final act was to give away the hard-won horse to a widow or someone in need, topping off their bravery with a show of generosity.

The iconic image of the war-painted Plains Indian chasing down buffalo—or U.S. soldiers—on horseback, rifle raised at full gallop, belongs to a surprisingly short period of Native American history. The full flowering of Plains Indian horse culture lasted little more than a century, roughly from the 1750s to the 1870s, when it was ended by the Indian Wars and forced relocation to reservations.

At its height, the “Horse Nation” of the Plains Indians included the militant Comanche, who were “probably the finest horse Indians of the Plains,” says Viola, in addition to the Cheyenne, Arapaho, Lakota (Sioux), Crow, Gros Vent Nez Perce and more.

“There were about a dozen very prominent horse tribes that went all the way from the Canadian border to Mexican border and they were the ones that confronted all these wagon trains and ‘Manifest Density,’” says Viola. “Because they were such good horse people, they were very effective at disrupting westward expansion and that’s why the Army had so much trouble with them.”

Eventually, the only way the federal government could defeat the Indians was to hire some of the best Plains Indian horsemen to be U.S. Cavalry. Her Many Horses says that after defeating the Plains Indians, the Army would sometimes slaughter the Indian’s horses so they would stay on the reservations and become farmers instead of going back to the “old ways” of hunting and raiding.