The Stable is a building introduced in the Classical Age. It augments your barracks and allows you to build mounted units, which are infantry on horses. Despite being on a horse, they are still considered foot soldiers. Mounted units typically have higher movement speeds as well as a higher attack than regular infantry. However, being on a horse makes them a large, and easy to hit target. This causes them to have an overall low defence. This makes them much better at attacking than infantry, and also allows them to be sent in small groups to check the enemy's units. It is replaced with the Vehicle bay in the Modern Age.