Before the stirrup was invented, there were only so many ways to fight on a horse, especially with armor. The Cataphract is the near the highest achievement of their technological era with medium armor on both horse and rider. The Cataphract moves as cavalry, quickly but nowhere horses can't go. The horses define the speed and precision of their movement but the rider controls how much damage gets done to their enemies.
Base Social Class
Cataphracts are always Peer units. This means every time you 'craft' one in a Recruitment/Training building, you are taking them from your local population. They still take up the same housing space and Happiness in their home District but they also can now be accessed in the Garrisons and will fight in defense of their district and settlement.
Cataphracts are recruited from the Peer population. If there are any unemployed Peers, the recruit function will choose them first. Because Cataphracts are inherently Peers, they require hiring cost and payment in Gold Florins.
Base Character Class
In order to increase variation between NPC units, each unity type is modeled after one of the 25 Hero classes. Many of the units are modeled after Soldiers, their main purpose being to inflict damage. The Cataphract on the other hand is a peer cavalry unit and thus their attributes and stats are based on the Cavalier hero class.
Training each unit of Cataphract requires a measure of Steel Ingots, Horses and Meat. Players have noted in the past that deconstructing a 'unit' will often leave Meat in your inventory. This is not people meat but a representation of what was used to recruit them. The Ingots are for all the armor and weapons they'll need and the Horses are obvious.
Each Unit can be equipped with one to three types of equipment based on their specialty and inherent social class. As a Peer unit, Cataphracts can equip 3 types of gear, along with their weapon type. They can wear Scale armor and a Helmet and you can, if you want, equip them with one of the specially trained personal Horses. Every Cataphract can equip a Sword item, but they'll still fight if you don't give them one.