These units are from the Iron age. A Legionnaire has the highest defense among the Iron age units, but has a moderate attack and slow speed. They have a defense bonus on plain terrain and a combat bonus against light units, like other Heavy units.
These units are effective against both melee classes and fast units, but are vulnerable to both ranged classes, as both have combat bonus against Legionnaires. In addition to their slow speed, they are usually killed without attacking any unit when encountered with several ranged units and artillery units.