Age of Empires II: The Age of Kings/Cavalry

Cavalry is any unit that rides a horse. (And the Persian unique unit, the War Elephant.) They are mostly quite fast with good Line of Sight (LOS). They are mostly created at the Stable. Cavalry units are: Basic:  Scout Cavalry, light melee cavalry, designed for scouting, resistant to conversion. Available Feudal Age. Stage 2: Light Cavalry, light melee cavalry, stronger than Scout Cavalry, resistant to conversion, archers, towers. Strong against Monks, archers, cavalry archers. Weak against infantry, knights. Available Castle Age. Stage 3: Hussar, light melee cavalry, stronger than Light Cavalry, resistant to conversion, archers. Attack bonus vs. Monks. Weak against infantry, knights, camels. Basic:  Knight, heavy melee cavalry, fast. Available Castle Age. Stage 2: Cavalier, heavy melee cavalry, fast. Stronger than Knight. Available Imperial Age. Stage 3: Paladin, heavy melee cavalry, fast. Stronger than Cavalier. Available Imperial Age. Note: Frankish Knights, Cavaliers and Paladins get +20% HP. In a multiplayer game, the Knight unit group of everyone on a Frank's team gets +2 LOS. Basic:  Camel, heavy melee cavalry, fast. Attack bonus vs. Cavalry. Available Castle Age. Stage 2: Heavy Camel, heavy melee cavalry, fast. Stronger than Camel. Attack bonus vs. Cavalry. Available Imperial Age. Note: Saracen unique tech, Zealotry, gives camels +30 HP. Many civilizations have unique cavalry units. A particularly noteworthy one, in my opinion, is the Mameluke, the Saracen unique unit. It is an anti-cavalry unit that can also deal with most other types of unit. A group of five can kill a Paladin in a bit more than one volley. (They throw swords.)