The stats can be upgraded from the technologies found in the Storage Pit and they also benefit from the nobility upgrade, which increases the hit points from 150 to 172.
All Cavalry deals a +5 damage bonus against all melee infantry units except for Academy units. It can be upgraded in the Iron Age to Heavy Cavalry and Cataphract. This unit is available to most civilizations, with the exception of the Egyptians and the Sumerians. They are a good base for an early raiding army, but become quickly obsolete with Iron Age technologies.
"Horses were domesticated around 4000 BC for use as work animals. They first appeared in the Middle East around 2000 BC but were kept only as expensive pets. Gradually they were found useful in the civilized world as draft animals, but were rarely ridden. The concept of cavalry was introduced to the Assyrians from the plains of Russia during the dark age that followed the catastrophe of 1200 BC. The Assyrians added cavalry to their armies in order to fight the barbarians on the plains to their north. Israelite king Solomon was renowned for his large cavalry force. It eventually became clear that cavalry was more efficient than chariots. Two men, each on his own horse, were more useful than two men in a chariot that could be disabled with increasing ease. Cavalry was cheaper to maintain than chariotry and could enter more difficult terrain, but was no less fast and intimidating to infantry."