By Fire and Sword II: Mercenary Reiters

Reiters, as a military formation, appeared in in the 16th century in the northern German states. Mercenary cavalry was equipped with a pair of pistols, a broadsword sometimes with arquebuses. Some of the soldiers also used armor - in general the equipment of a unit depended on the contract signed by its colonel and the extent to which he complied with it. Reiters were organized into companies and fought in six ranks and doubled (tightened) their ranks by forming three while charging. Even though the caracole was sometimes still in use, reiters favored melee, in which they engaged after shooting a volley with pistols.