Taming and domestication were not single events. They were a slow, stop-start process, full of setbacks, playing out over generations and across vast regions, before full domestication set in shortly before 2000 BCE.
"Horses were already being used in sophisticated, widespread ways before we could pin down full domestication. That gap reshapes how we understand human history," says
Professor Volker Heyd , co-lead author of the research.
"The role of horses in major historical developments is almost too vast to measure, hence the saying that the world was conquered on horseback," Heyd says.
From the sweeping movements of Eurasian nomadic groups such as the Huns, Avars, Magyars, and the Mongol Empire, to their decisive use in warfare (well into World Wars I and II), horses have been central to human conflict and expansion. They also accompanied conquistadors over the Atlantic to the Americas and served as the primary means of transport across much of the world until the rise of industrialisation and motorisation.
The wheel, the horse, and the words we still speak
Today, truly wild horses no longer exist. Even Przewalski's horse , long held up as a living relic of the wild, is now known to descend from early domesticated populations, showing how deeply humans have shaped horse populations over time.
The timing matters. Around 3,500 to 3,000 BCE, steppe populations began pushing east and west across Eurasia. They brought the wheel with them. Cattle pulled the first wagons. Horses came at the same time. A rider could cover ground in hours that a wagon took days to cross but both were key innovations in mobility and transport, revolutionizing human society.
Researchers now link that leap in mobility to the spread of Proto-Indo-European languages. The horse carried people. And with them, words. The languages spoken across much of Europe and Asia today trace back to those early riders and wagon drivers.
"Today, horses are a source of attraction, companionship, and friendship for many people. Therefore, it is important to learn about the earliest stages of human–horse relationships and how this unique partnership first emerged," Volker Heyd says.
