Equipment and Tactics
Equipment and tactics varied, but cataphracts generally wore heavy armor of mail, horn, or thick quilted cloth, carried a shield, sat an armored horse, and charged with lances in a tight knee-to-knee formation. Most armies' cataphracts would be equipped with an additional side-arm such as a sword or mace, for use in the melee that followed the charge. Some wore armor that was primarily frontal rather than providing equal protection all around, and sometimes likewise for the horse armor. In some armies cataphracts were not equipped with shields, particularly if they had heavy body armor.
Many cataphract types were equipped with bows in addition to their lances and heavy armor, to allow them to engage the enemy from afar before charging. Cataphract archery was sometimes used tactically in disciplined formations where half the cataphracts stood facing the enemy as an armored fence while the other half looped through the line to shoot and then back behind it to reload, increasing their safety against return fire from the enemy. Cataphracts without bows are sometimes referred to simply as lancers.
Some later cataphaphract types were also equipped with heavy darts to be hurled at the enemy lines during a charge, to disorder the defensive formation immediately before the impact of the lances. With or without darts, a cataphract charge would usually be "shot in" by foot or horse archers to either side, or by additional cataphracts who would charge in turn after having shot in the first assault. Some armies formalized this tactic by deploying separate types of cataphract, a very heavily armored bowless lancer for the primary charge and more conventional lance-and-bow cataphracts for supporting units.
Related Types
The Romans used cataphracts only late in their history, and even then primarily in the East. In addition to ordinary cataphract types they sometimes fielded a very heavy type called a clibanarius (pl. clibanarii), named after an iron oven due to their enclosed metal armor. They also formed one exotic experimental unit of scythed chariots with cataphract lancers mounted on the chariot's horses.
Nations in the Middle East occasionally fielded cataphracts mounted on camels rather than on horses, with obvious benefits for use in arid regions.