One thousand years ago, archers rode horses across the landscape of Hungary. They were probably intimidating, possibly threatening, and definitely adventurous, but just like equestrians today, they also fell a lot.

These horse riders remain a mystery. Who were they? Where were they from? When did they start riding horses? To answer these questions, an international team of scientists set out to find a way to identify horse riders from just their skeletons, using the fact that horse riders tend to fall. 

The researchers examined skeletons from a cemetery of well-known horse riders in Hungary dating to the 10th century CE. Riders in the cemetery were identified by horse riding equipment and horse bones in their graves. However, scientists could not be sure that skeletons without artifacts in the Hungarian cemetery never rode horses.  Therefore, they also investigated skeletons from another group of people from 20th century Portugal that definitely did not ride horses.

They found that upper body fractures were more common among riders, and that fractures of the clavicle (collar bone) were significantly more common among the Hungarian riders than the 20th century non-riders. To figure out if these fractures could be caused by horse riding, researchers turned to modern equestrians. Sure enough, fractures of the upper body, especially the clavicle, are some of the most commonly reported injuries in modern day equestrians.

The researchers argue that, in combination with other skeletal changes, clavicle fractures can be used to identify horse riders from just their skeletons. Being able to identify horse riders in the past could help researchers find the first horse riders, shedding light on the ways horse riding shaped human history.