Although infantry was the lifeblood of the Roman army, cavalry provided a crucial element of the Roman military system across the empire. During excavations of the barracks at Segedunum on Hadrian’s Wall, the mystery of where the horses were kept was solved. “We had never been able to identify stables in Roman forts because we were always thinking of separate stables and soldiers’ barracks,” says Segedunum archaeologist Nick Hodgson. “But since we were able to recognize the long, deep pits for the horses’ waste under the barracks’ floors, it’s universally recognized that the horses and men were accommodated together—three horses and three troopers to a room.” This allowed the men to keep a close eye on their very valuable roommates.