The War Elephant is a heavy cavalry unit in Age of Empires that can be trained at the Stable once the Iron Age is reached. War Elephants are very slow and rather expensive but pack a massive attack (including splash damage) and high health. War Elephants are only available to some civilizations.
War Elephants have the most hit points of any land unit and an attack that damages all enemies around them. Their downside is that they are slow and therefore a great target for enemy siege units. Their slow speed also makes them very prone to conversion by enemy Priests. Civilizations that have bonuses for War Elephants include the Phoenicians, Persians, and the Carthaginians. Persian War Elephants are 25% faster while the Phoenicians can train them at a cheaper cost. Carthaginian War Elephants have 25% more hit points.
Elephants were tamed in antiquity but never domesticated. They were most useful as beasts of burden, but were employed in battle by several cultures, including the Phoenicians, Persians, and Indians. Elephants were much more intimidating than horses and much tougher as well. In addition, horses avoided elephants, making elephants, in theory, a great weapon against enemy cavalry. In practice, unfortunately, elephants rarely proved useful. They were difficult to acquire,train, and maintain. Hannibal attempted to take elephants across the Alps to attack Rome, but only one survived. No account of Alexander the Great's battles makes any mention of Persian elephants being effective. Elephants were difficult to control in battle and were likely to charge in any direction but the one desired, especially after being wounded. They were apparently more dangerous to friend than foe, being already nearer to friends and most likely to charge away from perceived danger through the friendly army arrayed around them.