New research based on human skeletons found in Bulgaria, Hungary, and Romania suggests that the ancient Yamnaya people living there were riding horses around 5,000 years ago, seemingly earlier than evidence from other regions. The findings could challenge theories that the Botai people of modern-day Kazakhstan were the first to domesticate and ride horses. The authors of the new study, published in Science Advances, cite "changes in bone morphology and distinct pathologies associated with horseback riding" suggesting the Yamnaya burials in Eastern Europe represent "the oldest humans identified as riders so far." The Yamnaya lived in what's now western Russia and then Eurasia.