The Heavy Cavalry is a powerful cavalry unit in Age of Empires. The Heavy Cavalry is an upgrade of the Cavalry, so it is much stronger in attack and has more armor. It is available once the Iron Age is reached. Heavy Cavalry can be upgraded to Cataphracts at the same Age for 1,600 food and 750 gold once Metallurgy is researched.
"Heavy cavalry was distinguished from other cavalry by equipment and battlefield role. It was considered heavy because the warriors and horses usually wore some metal armor, including breastplates, helmets, and greaves. The horses were also oversized to more easily carry an armored man and to intimidate foes. While most cavalry acted as skirmishers and scouts on the battlefield, heavy cavalry was a shock weapon, held back for the proper moment to charge into enemy formations and ride them down. Heavy cavalry was rare in antiquity because the saddle and stirrup had not yet been invented. It took an exceptional rider to ride into a shock battle and use a lance effectively. The most famous heavy cavalry of the time was the Companion cavalry of Alexander the Great. These men were horsemen from birth on the plains of Thessaly and Macedon. Part of their devastating success in battle against the Persians may have been due to the novelty of their wedge-shaped charges, unprecedented at that time."