Here’s a story, told by Herodotus, about the fierce female warriors known as Amazons. Many thousands of years ago, a group of Greek raiders ventured into what is now northern Turkey. Travelling across the steppe, they came across a group of warrior women. The Greeks kidnapped them, locked them in the holds of their ships, and set sail for home. But the Amazons escaped. They recovered their weapons and killed their captors. Because they were horsewomen, and didn’t know how to sail, the ships drifted far off course. Eventually, though, they landed in the Crimea. The Amazons went ashore and stole some horses. They started marauding, gathering loot, and building up their strength.

Nearby, there happened to be a settlement of Scythians. Most Scythians were nomadic, horse-riding people of the steppe. But these were Royal Scythians—wealthy traders who had settled in towns. To avoid being raided, the Royal Scythians sent out scouts, who discovered that the strange marauders were Amazons. The Scythians found this intriguing. They had planned to send soldiers to kill the marauders; instead, they assembled a party of nice young men. Life in town was luxurious, but it lacked a certain something: the Royal Scythian women mostly stayed indoors, doing chores and feeling bored. Maybe a few fearless, untamed Amazons could spice things up. The band of bachelors travelled out onto the steppe and found the horsewomen. They set up camp and hung around until, one afternoon, one of them encountered a single Amazon, walking alone. “Wordlessly he made advances and she responded,” Adrienne Mayor writes, in “The Amazons: Lives and Legends of Warrior Women Across the Ancient World.” “They made love in the grass. Afterward, the Amazon gestured to indicate that he should return the next day to the same spot—and to bring a friend. She made it clear that she would bring a friend too.”

Soon, the Amazons and the Scythians consolidated their camps, and the young men extended a proposal: Why not come back and live with them? They had money, houses, and parents—surely settled life would be better than life on the steppe. The Amazons, incredulous, made a proposal in return: Why not leave town behind and live as they did: riding, raiding, and sleeping under the stars? The men packed their things. Herodotus reports that the Sarmatians, the people descended from that union, created a society characterized by gender equality, in which men and women led the same sort of life. It’s a story, Mayor points out, in which the “answer to the question of who will be dominated and tamed is no one.”

The natural question, when you’re faced with a story like this, is: How true is it? In “Amazons,” Mayor—a classicist, based at Stanford, who is by all accounts the world’s leading expert on ancient female fighters—argues that, even if it is not literally true in all its particulars, it is still broadly true. The evidence, she writes, points to the fact that there really were Amazons: in some archaeological digs in Eurasia, as many as thirty-seven per cent of the graves contain the bones and weapons of horsewomen who fought alongside men. (“Arrows, used for hunting and battle, are the most common weapons buried with women, but swords, daggers, spears, armor, shields, and sling stones are also found,” Mayor writes.) These were the women the Greeks encountered on their expeditions around the Black Sea; they inspired similar stories among travellers from ancient Persia, Egypt, China, and other places. In Greece, they were objects of romantic fascination. Their societies, in which both men and women were able to embody the martial virtues, provided a counterpoint to Greek society, in which only men could be valorous. Greek stories about Amazons, Mayor argues, expressed the ancient Greeks’ yearning for gender equality.

Mayor doesn’t teach; she is a full-time scholar and researcher in the Classics department at Stanford, where she studies the folklore, myth, and science of the ancient world. (Her 2010 biography of Mithradates, the “Poison King,” who tried to take over Rome, and who inspired fear as a deadly toxicologist, was a finalist for the National Book Award.) “The Amazons,” Mayor told me, has been in the works for decades. “As a kid, I was a tomboy,” she said. “I played with toy cowboys and Indians and soldiers, and noticed there weren’t any girls. Then, as a college student at the University of Minnesota, during the Vietnam War, I got interested in military history; I just thought that stories from wartime have the very best of human behavior and the very worst. I got permission to take R.O.T.C. classes (back then, there weren’t any girls allowed). Then I took classes in ancient Greek and Roman history. I was fascinated by the war stories about Amazons. In 1990, I proposed an article about Amazons to Military History Quarterly, and it was turned down. So I searched around, found a male co-author, and had the guy propose the same article, and it was accepted.” It’s a pleasant coincidence that a critical mass of evidence about the historical Amazons has coalesced at the same time that our culture, in characters such as Katniss Everdeen, is settling into an Amazon moment. (Earlier this year, Jill Lepore wrote about how the character of Wonder Woman was based, in part, on stories about Amazons.)

For a long time, Mayor said, “Most people argued that the Amazons on Greek vases were purely symbolic—that they represented, for example, young women who weren’t yet married.” The interpretation has been challenged by “a wealth of archaeological discoveries that show that there were women who behaved like Amazons—who wore the same clothes, who used weapons, who rode horses, and who lived at the same time as the ancient Greeks.” It’s now possible to know, in a concrete way, what Amazon life was like. The Amazons were likely Scythian nomads who travelled the territory north of the Black Sea—roughly between the Balkans, to the west, and the Caucasus, to the east. They were not, as Mayor puts it, “man-hating virgins,” but simply members of “a people notorious for strong, free women.” (No one knows where the word “Amazon” comes from—it isn’t Greek—but there are a few possibilities, including an ancient Iranian word that means “warrior.”) The Greek way of war centered on infantry—that is, on armored, brawny men. But, on the steppe, “the horse was the great equalizer, along with the bow and arrow, which meant that a woman could be just as fast, just as deadly, as a man,” Mayor writes.

Amazons spent days at a time on horseback; often, their legs were bowed from so much riding. Their lives followed a yearly cycle, with occasional large gatherings for feasting, funerals, athletic contests, and “purifying saunas.” The Greeks credited the Amazons with inventing trousers, and the Amazons wore them with long-sleeved tunics and pointed hats with ear-flaps. (It was cold out on the steppe.) They drank fermented mare’s milk—you freeze it, then skim off the ice to increase the alcohol concentration. They smoked cannabis, which is indigenous to Central Asia. They were elaborately tattooed. They fought on foot, when they had to. (One study of Amazon skeletons with head wounds from battle-axes, Mayor reports, showed that “most of the blows were dealt by a right-handed opponent in face-to-face combat.”) There was fierce competition for territory and resources. Amazons domesticated dogs and hunted with eagles. It’s hard to know much about their spiritual lives, Mayor writes, but archaeological evidence and folktales can give us “an impressionistic sense of the beliefs of the women archers of Scythian lands known as Amazons, an intangible mosaic of animism, totemism, magic, of sacred fire and gold, of reverence for Sun, Moon, sky, earth, nature, wild animals, fantastic creatures. And horses.”