Freikorps (pronounced [ˈfʀaɪ̯ˌkoːɐ̯], "Free Corps") were German volunteer units that existed from the 18th to the early 20th centuries, the members of which effectively fought as mercenaries, regardless of their own nationality. In German-speaking countries, the first so-called Freikorps ("free regiments", German: Freie Regimenter) were formed in the 18th century from native volunteers, enemy renegades and deserters, and criminals. These sometimes exotically equipped units served as infantry and cavalry (or more rarely as artillery), sometimes in just company strength, sometimes in formations up to several thousand strong; there were also various mixed formations or legions.