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. The Prussian von Kleist Freikorps included infantry, jäger, dragoons, and hussars. The French Volontaires de Saxe combined uhlans and dragoons.
In the aftermath of World War I and the German Revolution of 1918–19, Freikorps were raised as right-wing paramilitary militias to fight against the left wing in the newly formed Weimar Republic. "They engaged in bloody confrontations with republican loyalists and engineered some of the more notorious assassinations" of the Weimar period, and are widely seen as a "precursor to Nazism". An entire series of Freikorps awards also existed.
The very first Freikorps were recruited by Frederick the Great during the Seven Years' War. On 15 July 1759, Frederick ordered the creation of a squadron of volunteer hussars to be attached to the 1st Regiment of Hussars (von Kleist's Own). He entrusted the creation and command of this new unit to Colonel Friedrich Wilhelm von Kleist. This first squadron (80 men) was raised in Dresden and consisted mainly of Hungarian deserters. This squadron was placed under the command of Lieutenant Johann Michael von Kovacs. At the end of 1759, the first 4 squadrons of dragoons (a.k.a. horse-grenadiers) of the Freikorps were organised. They initially consisted of Prussian volunteers from Berlin, Magdeburg, Mecklenburg and Leipzig but later recruited deserters. The Freikorps were regarded as unreliable by regular armies, so they were mainly used as sentries and for minor duties.